ABSTRACT
In Taiwan millions of livestocks are raized for animal protein supply, however most of the feed ingredients are imported. For food safety and sustainable environment, explore the available locally produced feed resources is a more and more urgent issue. There are lots of by-products produced from agriculture and food processing. How to collect, combine, preserve, transport, formulate into diet, and improving feed value, etc needs to be worked out. The previous and ongoing research work is introduced. The high moisture content (> 90%) of pineapple pulp (PP) restricts its utilization. It was suggested PP could mixed with RS at 10:1 fresh weight ratio, for wheat bran or Flammulina velutipes (FC) spend substrate, 6:1 and 1:1 was recommended. After PP+RS silage offered 0, 4, 8, or 12 kg (fresh weight in diet) to Holstein cows, 12 kg a day supported normal yield, milk fat percent and was recommended. Unfortunately, WSC was almost used up by lactic acid bacteria when ensiling. No response to our high protein and gravity expectation, but PP+WB still performed as a good alternative feed source that 8% in lactating goat dit was suggested. The proper adding ratio for PP+FC silage for milking goats was 8% in diet and for Holstein cows 8% to 12% is suitable. About 15% of sweet potato will be eliminated. The sub-quality sweet potato (SSP) still holds the strong potency of trypsin inhibitor (TI). By ensiling, 28.7% of the activity of TI was diminished. SSP+WB mixed at 10:1 ratio and added into diet to substitute by-product part to occupy 0% to 13.5% diet dry matter. This addition way caused the significantly 10% decrease in milk fat percent by which indicated the rumen acidosis problem. Diet NDF decreased by 24% and NFC increased by 38% when 0% compared with the 13.5% diet. To avoid the health risk, SSP+WB was added again into diets but directly substituted the corn in grain mixture from 0% to 70%. Holstein cows responsed better fed 30 to 50% corn substituting diets, and lactating goats more tolerable to SSP could stand for 30% to 70% corn substituting diets. Another case was the feeding of tomato pomace+corn meal (10:1) silage. Lactating goats accepted when added into diets from 6% to 10% dry matter, however, cows did not like tomato pomace silage at all. How high the by-product could be used in diet for milking ruminant is influenced by many factors. By means of the common used by-product, mid-producing cows responsed normally with diets added by-product from 10% to 30%, the 333 diet was recommended. Besides the feed utilization, adoption of by-product in diet decreased rumen methane emission by 9% and 22% and carbon dioxide by 10% and 13% when Rusitec system was offered diets having 10%, 20% or 32% by-product. This might be contributed to the high short fiber and high digestibility that to replace the long fiber and grain amount in diets. Utilization of by-product not only to cut down the greenhouse gas emission during transpotation but also reduces it from the rumem. The off-bottom of mushroom during shaping process was dried and fed to weaning goat kids. Off-bottom from Pleurotus eryngii and Flammulina velutipes and added at 1.5% each stimulated the best daily gain and significant lower diarrhea occurance at the 3rd month of trial. It is thought the polysaccharides and triterpenoids in mushroom are benefitial to health. Agriculture and food processing by-products could be valuable feed resource. More studies are needed to verify the proper ratio, wrapping technique, safe transpotation, nutrition balance knowledge, and the price. It is planned to set up the industry link that really estabalish the business.
Keywords: By-products from agriculture and food-processing, feed, Holstein dairy cow, Alpine dairy goat
INTRODUCTION
By-product is one important source as feed for ruminant. Wet brewer’s grains, sorghum distillers’ grains, soybean pomace, wheat bran, and pelleted soybean hull all are commonly used in diets. There are lots of by-products with low quality, short season, small quantity, or high in water content and thus are discarded. This is worth our awareness to change. 2016 Agricultural statistics yearbook of Taiwan indicated that the planted areas of rice are about 27.47 million hectares each year, and it is estimated that about 5 - 6 tons of rice straw are produced in each hectare (Tien et al., 2013); therefore, the production of rice straw can reach above 150 million tons in Taiwan. Since rice straw is not an easily digestible high fiber by-product, which contains 25 - 45% of cellulose, 18 - 30% of hemicellulose, and 10 – 15% of lignin (Van Soest, 2006). Traditionally, it can be used as a feed ingredient in ruminants but shows lower animal performance (Van Soest, 2006; Sheikh et al., 2017). The edible mushroom could secrete enzymes to decompose lignin, including laccases, manganese peroxidase, and lignin peroxidase (Hammel et al., 1993; Martínez et al., 2005). It is estimated that 20 million tons of spent mushroom substrates are produced annually (Chen et al., 2013), which caused an urgent problem for farmers to deal with plenty of mushroom waste substrates.
Pineapple pulp is the residue from pineapple cake, can or juice processing factory. It was estimated the pulp occupied about 25 to 33% of whole pineapple fruit. In 2016 data, there was 400,000 tons of pineapple harvested. This meant about 100,000 tons to 130,000 tons of pineapple pulp produced (Guerout, 1975). Sweet potato is an energy source and riches in starch. Diverse products from sweet potato are more and more popular in food market. The plant area is stably increasing and reaches to 10,310 hectares. Yearly production quantity comes to 241,694 tons. There is 15% sweet potato would be graded off due to size or shape. The quantity of sub-quality sweet potato could reach 36,254 tons per year and the handling pressure is high. The activity of anti-nutrient factor trypsin inhibitor is high in sweet potato. From previous study, ground rice grain and sweet potato were used in feeding trial to replace the imported corn. Results suggested except the layers, ground rice grain could replace 50 to 100% corn in diets. But due to trypsin inhibitor, sweet potato could only replace 20 to 30% corn in diets to avoid the growth retardation. The useage of sweet potato in monogastric livestock is highly restrickly. It is wondered if going through acidic ensiling process and rumen microbe degradation, could trypsin inhibitor be destroyed. Relative studies are still in progress.
UTILAZATION OF BY-PRODUCTS AS FEED SOURCES
Pineapple pulp
Pineapple pulp (PP) which is rich in water soluble carbohydrates (ca. 26%) and fiber (ca. NDF 43%) is the residue from pineapple cake and juice processing. The high moisture content (> 90%) limits its preservation, transportation and utilization for feeds. Before making PP into good silage, it is necessary to run in vitro screens to get the proper mixing formulations. Highly fibrous spent mushroom substrate and and rice straw (RS) are drier and might be improved when mixed with the acidic PP during ensiling. PP and Flammulina velutipes (FC) spend substrate were formulated into eight ratio silages (PFS) and 1:1 ratio (fresh weight) was recommended from its Flieg's scores, compositions, in vitro dry matter digestibility, and physical appearance. Same for PP and RS in vitro study, 10:1 mixing ratio (PRS) was chosen. And for wheat bran, the 6:1 ratio (PWS) was adopted for following animal evaluation trials (Fan et al., 2014).
In PRS study, a total of 40 head mid-lactating Holstein cows were assigned into four groups for replicate 28-day feeding trials. Four treated diets balanced for nutrition requirement included fresh PRS at 0, 4 kg, 8 kg, or 12 kg per day per cow. Results showed that cow performance fed with four diets were all similar (Table 1). The averaged dry matter intake, milk yield, percent of milk fat, milk protein, total solid, milk urea nitrogen, and somatic cell counts were all close among groups, there were 18.1 kg, 23.3 kg, 3.80%, 3.41%, 12.73%, 12.4 mg/dL, and 26.3*104/mL, respectively. Going through proper ensiling technique, the feeding values of pineapple pulp and rice straw could be effectively promoted. Addition of PRS up to 12 kg a day is acceptable for mid-lactating Holstein cows.
In Taiwan, the lower fat level and specific gravity of goat milk in hot summer is a problem. High starch and sugar might stimulate the milk fat and protein synthesis. In PWS study, PP holding high water soluble carbohydrate (WSC) and fiber together was expected to solve the low phenomenon. A total of 21 heads individually fed lactating Alpine goats with daily milk yield above 2.2 kg were assigned into 28-d feeding trials twice in summer. Diet included corn silage as major forage, grain mixture, and by-product. Control diet had 8% of wheat bran, and by substituting the wheat bran, PWS was added into trial diets at 4 or 8% diet dry matter. Results showed that dry matter intakes (averaged 2.07 kg), milk yield (2.66 kg), milk specific gravity (1.0305), milk fat (3.67%), milk protein (3.30%), milk lactose (4.07%), milk total solids (11.73%), and milk urea nitrogen (26.0 mg/dL) were similar among groups (Table 2). The WSC of PP was largely degraded by lactic acid bacteria during ensiling, from 26% to 1%. Although PWS added into diet 4% to 8% could not effectively promote the milk fat and gravity in summer, it had showed to be a valuable local feed resource for lactating dairy goats. A diet with 8% PWS is recommended (Fan et al., 2018).
Feeding values of PFS were evaluated from two lactation trials, dairy goats and Holstein cows. PFS was constituted by pineapple pulp and spent Flammulina velutipes substrate at 1:1 fresh weight ratio. Individually fed Saanen and Alpine goats and group fed Hostein cows were assigned into 28-d feeding trials twice. Control diet used corn silage and pangolagrass hay as main forage. By substituting the main forage, PFS was added into trial diets at 4, 8 or 12% diet dry matter. Results showed that the dry matter intake and milk yield of goats fed 4% PFS were higher than those fed 12% PFS diet (P < 0.05, Table 3). However, goats fed 4% PFS diet had the lower milk fat percent than the other groups (P < 0.05). For Hostein cows, intake (averaged 18.8 kg), milk yield (averaged 23.5 kg), and milk compositions were all similar among groups. In conclusion, combination of PP and FC at 1:1 ratio is a proper formulation for these two by-products of high quantity. PFS could be an alternative feed source for lactating dairy goats and Holstein cows. A diet with 8% PFS is suggested for lactating dairy goats and diets containing 8% to 12% of PFS are suitable for Holstein cows to receive (Fan et al., 2014).
The proper formulation strategy of sub-quality sweet potato
Sweet potato products are more and more popular in human food markets. Due to strick quality control, it is estimated that 15% of sweet potato is discarded because of their shapes or sizes. This off part resulted in proximately 36,254 tons a year. Sweet potato provides rich starch like corn. It was aimed to explore the proper ensiling method for sub-quality sweet potato (SSP) and also the proper formulation way in diets for ruminants so as to promote its recycle.
In the first year study, SSP mixed silage constituted by SSP and wheat bran (SSP+WB) at 10:1 fresh weight ratio was used in the Holstein lactating cows feeding trial. By substituting the by-product part in diet, wet brewer’s grains and soybean hull pellet, SSP+WB silage was added into diets to occupy 0, 4.5%, 9%, or 13.5% of dietary dry matter. It was equal to 0, 3, 6, or 9 kg per day per cow as fed basis. The same grain concentrate containing about 60% of corn was offered to all four groups. A total of 28 Holstein cows with daily milk yield above 23 kg were randomly assigned into four groups and group fed in the wet-padding ventilation barn for 24-day feeding trial twice.
SSP has the high potency of anti-nutrient factor trypsin inhibitor and needs awareness. It was shown in this study ensiling process could effectively decrease the trypsin inhibitor activity of SSP by 28.7%. Regarding the response from cows, the main effect from adding SSP+WB silage was shown in the lowered milk fat percent (Table 4, Fig. 1). Contrast comparison showed milk fat percent decreased by 9.7% between control group and SSP+WB added three groups (3.76 vs. 3.40%, P = 0.023). Dry matter intake and milk yield were tended to increase following the increasing ratio of SSP+WB in diets. Dry matter intake of cows increased by 11% (19.6 kg vs. 21.8 kg, P = 0.023). Milk yield increased not so parallel (24.1 vs. 25.7 kg, P = 0.31). The intake and lactating responses were postulated as the results of low fiber and high starch content in SSP+WB diets. Comparing control with SSP+WB 13.5% two groups, neutral detergent fiber (NDF) content in diets decreased by 24% from 42.2% to 32.1% and non-fibrous carbohydrate (NFC) on the contrary increased sharply by 38% from 31.0% to 42.8%. The most concern is the lower milk fat percent which has strong correlation with rumen acidosis.
To avoid the rumen health problem, in the second year study the SSP+WB silage was added into diets by substituting the corn in grain mixture. Four diet treatments had their own grain mixture formulation. A total of 28 heads each of Holstein cows and Alpine goats were assigned into four groups for 28-day feeding trial twice. SSP was added to replace 0, 30%, 50%, or 70% of corn in grain mixture (dry matter basis). This meant there were 0, 4.8%, 8%, or 11.3% of diet dry matter that were applied as SSP+WB silage. Results from cow study showed that dry matter intake (ranged 21.0 to 22.0 kg per day) and milk fat percent (ranged from 3.72% to 3.81%) were similar among groups (Table 5). Cows fed SSP substituting 70% corn obviously affected the milk yield performance by 13% and 3.3 kg per day per cow. The 4.0% fat-corrected milk yield was 21.3 kg versus the other three groups’ average 24.6 kg. This elucidates the diet nutrition was more balanced for rumen health but the anti-nutrient factor of SSP was still exiting and influenced. In conclusion, for Holstein lactating cows SSP could substitute 30% to 50% of corn in diet properly. For lactating goats, the tolerant level for SSP in diets seemed to be higher than that of cows. Dry matter intake (ranged 2.15 kg to 2.31 kg), milk fat percent (ranged 3.55% to 3.68%), and milk yield (ranged 2.63 kg to 2.76 kg) of four groups were similar. Milk yield of 70% substituting group and control group were almost equal. Substituting 30% and 50% groups had numerical higher milk yield than control group (3.5% fat-corrected milk yield 2.82 kg vs. 2.69 kg, 5% increased). Income over feed cost was also promoted by 5 – 6%. In clusion from goat study, SSP could properly replace 30% to 70% of corn in diet. Replacing 30% to 50% made more profit. As a whole, feed formulation strategy of SSP needs to consider its anti-nutrient effect carefully. By substituting corn in diet is the more safe way for SSP re-utilization.
Goats and cows response to tomato pomace addition differently
Tomato pomace is the residue from ketchup or tomato juice processing. However, the high moisture content limits its transportation and preservation for feeds. To build up a friendly environment, the ensiling formula for tomato and its proper usage in diets for lactating goats and cows were studied. Tomato pomace and corn meal (TPC) were mixed at 10:1 fresh weight ratio and ensiled in big plastic bag. TPC had pH value of 3.71 and both dry matter and crude protein contents of 20%, respectively. A total of 20 heads of Saanen and Alpine goats were randomly assigned into four groups and raised in individual pens in a 28-d feeding trial. TPC silage was added into four treatment diets at 0, 6, 10 or 15% (DM basis) by substituting part of the distiller’s grains and corn in control diet. Results showed that four diets could support goats to have similar daily dry matter intake (1.91 to 2.03 kg), milk fat (avg. 4.32%), protein (avg. 3.20%), lactose (avg. 4.31%) and total solid (avg. 12.53%). Milk yield from goats fed 15% TPC silage diet was numerical lowered (2.34, 2.51, 2.58 and 2.24 kg). This trend was even obvious when expressed as 3.5% fat-corrected milk yield, 2.59, 2.78, 2.96, and 2.59 kg. In conclusion, tomato pomace could be well preserved when mixed with corn meal at 10:1 ratio. Diets supplemented with 6% to 10% tomato pomace+corn meal mixed silage improved the lactating performance of dairy goats and 10% inclusion was recommended (Fan et al., 2015).
However, when diets with 0 – 15% TPC silages were offered to Holstein cows, responses were different. Cows fed diets with TPC silage decreased their milk yield by 5%, decreased milk protein percent (Contrast statistic, P < 0.05) and increased milk urea nitrogen (P < 0.06, Table 6). Reason for the negative response was not known. Tomato pomace+corn meal silage is not a suitable feed for lactating Holstein cows shown in this study.
The level of by-products in diets
Many by-products have high amount of short fiber and high digestibility at the same time. This makes it possible to partially replace the long-fiber forage and also the high-starch grain mixture in diets. And this would contribute to decrease heat increment of forage when digested and avoid rumen acidosis problem when gain feeding is high. This characteristic is important for cows in Taiwan especially in hot and humid summer. In 2011, in our experiment dairy barn, the idea of high by-product 333 diet was applied. Diet for lactating cows were formulated to have 1/3 of forage, 1/3 of by-product, and 1/3 of grain mixture. From the rough comparison with the previous 2010 (diet contained about half forage and half grain) on milk yield performance, milk yield of all herd was improved, especially for the summer, from June to Sept. There was extra 3.8 kg milk per day per cow increased. It was postulated the 333 high by-product diet stimulated the feed intake and kept the healthier rumen.
To officially identify if the 333 diet could be used for lactating cows, a total of mid-production Holstein cows were randomly assigned into three diets including by-product at 10%, 20%, or 32% in dietary dry matter basis. By-products were common used wet brewer’s grains, sorghum distiller’s grains, soybean hull pellet, and wheat bran. Feeding trial lasted for 28 days and was replicated once. Results indicated that dry matter intake, milk yield, and milk efficiency were all similar for cows fed three levels of by-products. The performance was averaged 19.2 kg, 22.5 kg, and 1.17, respectively. Milk compositions and income over feed cost both were also not affected by by-product levels in diets (Table 7). These results implicated for mid-lactating Holstin cows diet formulated with 30% by-product was pretty acceptable.
To further understand the replacement influence of by-product to grain mixture, diets with fixed forage ratio 36% were designed to have control 333 diets, high by-product diets (37%, grain was cut to 27%), and high grain diets (37%, by-product was cut to 27%). Both high-producing Holstein cows and mid-producing Alpine goats were assigned in the replicate feeding trials. Results indicated all trait performances were similar among the three groups for both cows and goats (Table 8). By-products combined with wet brewer’s grains, sorghum distiller’s grains, soybean hull pellet, and wheat bran with high digestibility are of high feeding values. It is feasible to use them up to the high level 37% in diet and has no adverse influence (Lee et al., 2012; Fan et al., 2012).
MITIGATION OF GREENHOUSE GAS FROM RUMEN (RUSITEC STUDY)
Utilization of local feedstuff can reduce the carbon footprint of products, meats, milk, and eggs, from transpotation saving. Agricultural and food processing by-products proved to be valuable alternative feed resources for ruminants. Rumen is a big anaerobic fermentation tank that continuously produce high amount of methane. To reduce the global warming impact caused by ruminants the feed manipulation is thought to be one way of reducing the methane emission from rumen. The effect of adding by-products into diets on the methane emission were studied by means of the Rusitec (Rumen simulation techniques) system. Agricultural and food processing by-products, wet brewers grains, sorghum distillers grains, soybean hull pellet and wheat bran, were added into diets at 10%, 20% or 32% of dietary dry matter. Local corn silage, pangolagrass hay and low amount of imported alfalfa hay constituted the forage part and the other was corn-soybean grain mixture. Trial diets were fermented in the semi-continuous anaerobic fermentation system Rusitec for 10 to 12 days. Except the daily change of feed bag, fermentation gas was collected in gas bags and analyzed for methane and carbon dioxide by gas chromatograph. Results showed that the daily averaged pH values of fermentation liquid were 6.35, 6.34 and 6.30, and dry matter digestibility of three diets were 84.3%, 86.5% and 84.7% sequentially. Efficiencies of rumen microbial synthesis (g-microbe/g-organic matter disappearance) were tended to increase, 0.50, 0.55 and 0.58. Quantity of daily fermentation gases were 2.65, 2.53 and 2.50 L, respectively. The daily emission of methane and carbon dioxide reduced following the increasing proportion of by-products in diets (Table 9). Comparing 20% and 32% by-products with 10% by-products diets, daily output of methane could reduce by 9% and 22%, and for carbon dioxide 10% and 13% reached, respectively. From this Rusitec study, it is recommended the diet strategy of using higher level of local agricultural and food processing by-products is a beneficial way to reduce the greenhouse gas impact from ruminant raizing (Lee et al., 2016).
PROMOTINGTHE HEALTH OF WEANING GOATS
It is suggested the polysaccharides, triterpenoids, polyphenols, and flavonoids in mushroom might benefit the health of weaning goats. During the processing, shaping will cut off some bottom part of the mushroom. This bottom-off was estimated to have 1/10 of the whole mushroom weight, and resulted in about 7000 tons fresh weight a year. Effect of supplementation of mushroom bottom by-product in diets on growth performance and immune response of dairy goat kids around weaning period was evaluated. Mushroom off-bottom from Pleurotus eryngii and Flammulina velutipes were dried and ground. A total of 40 heads of 4-wk-old kids were randomly assigned into four groups for a 12-wk feeding trial. All kids received 150 g milk replaces in one liter per day until 8-wk-old. A corn-soybean meal basal diet was offered as the control group. Three supplemented groups were fed diets supplemented with 3% of Pleurotus eryngii, 3% of Flammulina velutipes, or the mixture of 1.5% Pleurotus eryngii and 1.5% Flammulina velutipes mushroom off-bottom. Feed and water were offered ad libitum. Growth performances and diarrhea index were measured. Results showed that kids fed four diets had similar feed intake and feed conversion rate. Supplementation of mushroom off-bottom increased the daily body weight gain, and kids fed the mixture diet achieved the higher gain compared with control group (P < 0.05, Table 10). Daily gains of kids in four groups were 146, 160, 165, and 173 g, respectively. Diarrhea index of kids showed the same trend that supplementation of mushroom off-bottom could decrease the occurrence of diarrhea. Diarrhea index decreased obviously (P < 0.05) of kids fed on the 3% Flammulina velutipes and the mixture mushrooms off-bottom diets during the 9th to 12th weeks of experimental period compared with control group. In conclusion, supplementation of the 1.5% of Pleurotus eryngii and 1.5% of Flammulina velutipes mushrooms off-bottom for goat kids is effective in improving their growth and health status (Shih et al., 2017).
CONCLUSION
For the past 15 years, global prices for feed ingredients and hay had increased sharply, causing higher production cost and food safety concern. Therefore, the need to explore available feed resources becomes more and more important. From our studies ensiling could be one economic way to preserve locally produced agricultural and food processing by-products as feeds for ruminants. Improving the feed values of some fibrous but high quantity residues is also an effective way to expand feed sources. Solid-state fermentation used in rice straw by spent mushroom substrate has shown great potential. Through the proper combination of by-products and the nutrition balance knowledge, all will influence the utilization of by-products. Note only the feed character, by-products could be helpful to livestock health and decreases the food mileage by means of lower methane emitted fom the rume. Fermented rice straw, pineapple pulp, spent mushroom substrate, sub-quality sweet potato, tomato pomace etc. all could be properly formulated into silage for feeding ruminants. More research work is needed. In the near future, we would like to try different sizes and formulas for by-products preserved as plastic wrapped round bales. It is believed that the diverse bale silage could promote the convenient transportation and hence set up the industry links, from production place to farms.
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Application of By-Products from Agriculture and Food-Processing as Feed Resources for Ruminants
ABSTRACT
In Taiwan millions of livestocks are raized for animal protein supply, however most of the feed ingredients are imported. For food safety and sustainable environment, explore the available locally produced feed resources is a more and more urgent issue. There are lots of by-products produced from agriculture and food processing. How to collect, combine, preserve, transport, formulate into diet, and improving feed value, etc needs to be worked out. The previous and ongoing research work is introduced. The high moisture content (> 90%) of pineapple pulp (PP) restricts its utilization. It was suggested PP could mixed with RS at 10:1 fresh weight ratio, for wheat bran or Flammulina velutipes (FC) spend substrate, 6:1 and 1:1 was recommended. After PP+RS silage offered 0, 4, 8, or 12 kg (fresh weight in diet) to Holstein cows, 12 kg a day supported normal yield, milk fat percent and was recommended. Unfortunately, WSC was almost used up by lactic acid bacteria when ensiling. No response to our high protein and gravity expectation, but PP+WB still performed as a good alternative feed source that 8% in lactating goat dit was suggested. The proper adding ratio for PP+FC silage for milking goats was 8% in diet and for Holstein cows 8% to 12% is suitable. About 15% of sweet potato will be eliminated. The sub-quality sweet potato (SSP) still holds the strong potency of trypsin inhibitor (TI). By ensiling, 28.7% of the activity of TI was diminished. SSP+WB mixed at 10:1 ratio and added into diet to substitute by-product part to occupy 0% to 13.5% diet dry matter. This addition way caused the significantly 10% decrease in milk fat percent by which indicated the rumen acidosis problem. Diet NDF decreased by 24% and NFC increased by 38% when 0% compared with the 13.5% diet. To avoid the health risk, SSP+WB was added again into diets but directly substituted the corn in grain mixture from 0% to 70%. Holstein cows responsed better fed 30 to 50% corn substituting diets, and lactating goats more tolerable to SSP could stand for 30% to 70% corn substituting diets. Another case was the feeding of tomato pomace+corn meal (10:1) silage. Lactating goats accepted when added into diets from 6% to 10% dry matter, however, cows did not like tomato pomace silage at all. How high the by-product could be used in diet for milking ruminant is influenced by many factors. By means of the common used by-product, mid-producing cows responsed normally with diets added by-product from 10% to 30%, the 333 diet was recommended. Besides the feed utilization, adoption of by-product in diet decreased rumen methane emission by 9% and 22% and carbon dioxide by 10% and 13% when Rusitec system was offered diets having 10%, 20% or 32% by-product. This might be contributed to the high short fiber and high digestibility that to replace the long fiber and grain amount in diets. Utilization of by-product not only to cut down the greenhouse gas emission during transpotation but also reduces it from the rumem. The off-bottom of mushroom during shaping process was dried and fed to weaning goat kids. Off-bottom from Pleurotus eryngii and Flammulina velutipes and added at 1.5% each stimulated the best daily gain and significant lower diarrhea occurance at the 3rd month of trial. It is thought the polysaccharides and triterpenoids in mushroom are benefitial to health. Agriculture and food processing by-products could be valuable feed resource. More studies are needed to verify the proper ratio, wrapping technique, safe transpotation, nutrition balance knowledge, and the price. It is planned to set up the industry link that really estabalish the business.
Keywords: By-products from agriculture and food-processing, feed, Holstein dairy cow, Alpine dairy goat
INTRODUCTION
By-product is one important source as feed for ruminant. Wet brewer’s grains, sorghum distillers’ grains, soybean pomace, wheat bran, and pelleted soybean hull all are commonly used in diets. There are lots of by-products with low quality, short season, small quantity, or high in water content and thus are discarded. This is worth our awareness to change. 2016 Agricultural statistics yearbook of Taiwan indicated that the planted areas of rice are about 27.47 million hectares each year, and it is estimated that about 5 - 6 tons of rice straw are produced in each hectare (Tien et al., 2013); therefore, the production of rice straw can reach above 150 million tons in Taiwan. Since rice straw is not an easily digestible high fiber by-product, which contains 25 - 45% of cellulose, 18 - 30% of hemicellulose, and 10 – 15% of lignin (Van Soest, 2006). Traditionally, it can be used as a feed ingredient in ruminants but shows lower animal performance (Van Soest, 2006; Sheikh et al., 2017). The edible mushroom could secrete enzymes to decompose lignin, including laccases, manganese peroxidase, and lignin peroxidase (Hammel et al., 1993; Martínez et al., 2005). It is estimated that 20 million tons of spent mushroom substrates are produced annually (Chen et al., 2013), which caused an urgent problem for farmers to deal with plenty of mushroom waste substrates.
Pineapple pulp is the residue from pineapple cake, can or juice processing factory. It was estimated the pulp occupied about 25 to 33% of whole pineapple fruit. In 2016 data, there was 400,000 tons of pineapple harvested. This meant about 100,000 tons to 130,000 tons of pineapple pulp produced (Guerout, 1975). Sweet potato is an energy source and riches in starch. Diverse products from sweet potato are more and more popular in food market. The plant area is stably increasing and reaches to 10,310 hectares. Yearly production quantity comes to 241,694 tons. There is 15% sweet potato would be graded off due to size or shape. The quantity of sub-quality sweet potato could reach 36,254 tons per year and the handling pressure is high. The activity of anti-nutrient factor trypsin inhibitor is high in sweet potato. From previous study, ground rice grain and sweet potato were used in feeding trial to replace the imported corn. Results suggested except the layers, ground rice grain could replace 50 to 100% corn in diets. But due to trypsin inhibitor, sweet potato could only replace 20 to 30% corn in diets to avoid the growth retardation. The useage of sweet potato in monogastric livestock is highly restrickly. It is wondered if going through acidic ensiling process and rumen microbe degradation, could trypsin inhibitor be destroyed. Relative studies are still in progress.
UTILAZATION OF BY-PRODUCTS AS FEED SOURCES
Pineapple pulp
Pineapple pulp (PP) which is rich in water soluble carbohydrates (ca. 26%) and fiber (ca. NDF 43%) is the residue from pineapple cake and juice processing. The high moisture content (> 90%) limits its preservation, transportation and utilization for feeds. Before making PP into good silage, it is necessary to run in vitro screens to get the proper mixing formulations. Highly fibrous spent mushroom substrate and and rice straw (RS) are drier and might be improved when mixed with the acidic PP during ensiling. PP and Flammulina velutipes (FC) spend substrate were formulated into eight ratio silages (PFS) and 1:1 ratio (fresh weight) was recommended from its Flieg's scores, compositions, in vitro dry matter digestibility, and physical appearance. Same for PP and RS in vitro study, 10:1 mixing ratio (PRS) was chosen. And for wheat bran, the 6:1 ratio (PWS) was adopted for following animal evaluation trials (Fan et al., 2014).
In PRS study, a total of 40 head mid-lactating Holstein cows were assigned into four groups for replicate 28-day feeding trials. Four treated diets balanced for nutrition requirement included fresh PRS at 0, 4 kg, 8 kg, or 12 kg per day per cow. Results showed that cow performance fed with four diets were all similar (Table 1). The averaged dry matter intake, milk yield, percent of milk fat, milk protein, total solid, milk urea nitrogen, and somatic cell counts were all close among groups, there were 18.1 kg, 23.3 kg, 3.80%, 3.41%, 12.73%, 12.4 mg/dL, and 26.3*104/mL, respectively. Going through proper ensiling technique, the feeding values of pineapple pulp and rice straw could be effectively promoted. Addition of PRS up to 12 kg a day is acceptable for mid-lactating Holstein cows.
In Taiwan, the lower fat level and specific gravity of goat milk in hot summer is a problem. High starch and sugar might stimulate the milk fat and protein synthesis. In PWS study, PP holding high water soluble carbohydrate (WSC) and fiber together was expected to solve the low phenomenon. A total of 21 heads individually fed lactating Alpine goats with daily milk yield above 2.2 kg were assigned into 28-d feeding trials twice in summer. Diet included corn silage as major forage, grain mixture, and by-product. Control diet had 8% of wheat bran, and by substituting the wheat bran, PWS was added into trial diets at 4 or 8% diet dry matter. Results showed that dry matter intakes (averaged 2.07 kg), milk yield (2.66 kg), milk specific gravity (1.0305), milk fat (3.67%), milk protein (3.30%), milk lactose (4.07%), milk total solids (11.73%), and milk urea nitrogen (26.0 mg/dL) were similar among groups (Table 2). The WSC of PP was largely degraded by lactic acid bacteria during ensiling, from 26% to 1%. Although PWS added into diet 4% to 8% could not effectively promote the milk fat and gravity in summer, it had showed to be a valuable local feed resource for lactating dairy goats. A diet with 8% PWS is recommended (Fan et al., 2018).
Feeding values of PFS were evaluated from two lactation trials, dairy goats and Holstein cows. PFS was constituted by pineapple pulp and spent Flammulina velutipes substrate at 1:1 fresh weight ratio. Individually fed Saanen and Alpine goats and group fed Hostein cows were assigned into 28-d feeding trials twice. Control diet used corn silage and pangolagrass hay as main forage. By substituting the main forage, PFS was added into trial diets at 4, 8 or 12% diet dry matter. Results showed that the dry matter intake and milk yield of goats fed 4% PFS were higher than those fed 12% PFS diet (P < 0.05, Table 3). However, goats fed 4% PFS diet had the lower milk fat percent than the other groups (P < 0.05). For Hostein cows, intake (averaged 18.8 kg), milk yield (averaged 23.5 kg), and milk compositions were all similar among groups. In conclusion, combination of PP and FC at 1:1 ratio is a proper formulation for these two by-products of high quantity. PFS could be an alternative feed source for lactating dairy goats and Holstein cows. A diet with 8% PFS is suggested for lactating dairy goats and diets containing 8% to 12% of PFS are suitable for Holstein cows to receive (Fan et al., 2014).
The proper formulation strategy of sub-quality sweet potato
Sweet potato products are more and more popular in human food markets. Due to strick quality control, it is estimated that 15% of sweet potato is discarded because of their shapes or sizes. This off part resulted in proximately 36,254 tons a year. Sweet potato provides rich starch like corn. It was aimed to explore the proper ensiling method for sub-quality sweet potato (SSP) and also the proper formulation way in diets for ruminants so as to promote its recycle.
In the first year study, SSP mixed silage constituted by SSP and wheat bran (SSP+WB) at 10:1 fresh weight ratio was used in the Holstein lactating cows feeding trial. By substituting the by-product part in diet, wet brewer’s grains and soybean hull pellet, SSP+WB silage was added into diets to occupy 0, 4.5%, 9%, or 13.5% of dietary dry matter. It was equal to 0, 3, 6, or 9 kg per day per cow as fed basis. The same grain concentrate containing about 60% of corn was offered to all four groups. A total of 28 Holstein cows with daily milk yield above 23 kg were randomly assigned into four groups and group fed in the wet-padding ventilation barn for 24-day feeding trial twice.
SSP has the high potency of anti-nutrient factor trypsin inhibitor and needs awareness. It was shown in this study ensiling process could effectively decrease the trypsin inhibitor activity of SSP by 28.7%. Regarding the response from cows, the main effect from adding SSP+WB silage was shown in the lowered milk fat percent (Table 4, Fig. 1). Contrast comparison showed milk fat percent decreased by 9.7% between control group and SSP+WB added three groups (3.76 vs. 3.40%, P = 0.023). Dry matter intake and milk yield were tended to increase following the increasing ratio of SSP+WB in diets. Dry matter intake of cows increased by 11% (19.6 kg vs. 21.8 kg, P = 0.023). Milk yield increased not so parallel (24.1 vs. 25.7 kg, P = 0.31). The intake and lactating responses were postulated as the results of low fiber and high starch content in SSP+WB diets. Comparing control with SSP+WB 13.5% two groups, neutral detergent fiber (NDF) content in diets decreased by 24% from 42.2% to 32.1% and non-fibrous carbohydrate (NFC) on the contrary increased sharply by 38% from 31.0% to 42.8%. The most concern is the lower milk fat percent which has strong correlation with rumen acidosis.
To avoid the rumen health problem, in the second year study the SSP+WB silage was added into diets by substituting the corn in grain mixture. Four diet treatments had their own grain mixture formulation. A total of 28 heads each of Holstein cows and Alpine goats were assigned into four groups for 28-day feeding trial twice. SSP was added to replace 0, 30%, 50%, or 70% of corn in grain mixture (dry matter basis). This meant there were 0, 4.8%, 8%, or 11.3% of diet dry matter that were applied as SSP+WB silage. Results from cow study showed that dry matter intake (ranged 21.0 to 22.0 kg per day) and milk fat percent (ranged from 3.72% to 3.81%) were similar among groups (Table 5). Cows fed SSP substituting 70% corn obviously affected the milk yield performance by 13% and 3.3 kg per day per cow. The 4.0% fat-corrected milk yield was 21.3 kg versus the other three groups’ average 24.6 kg. This elucidates the diet nutrition was more balanced for rumen health but the anti-nutrient factor of SSP was still exiting and influenced. In conclusion, for Holstein lactating cows SSP could substitute 30% to 50% of corn in diet properly. For lactating goats, the tolerant level for SSP in diets seemed to be higher than that of cows. Dry matter intake (ranged 2.15 kg to 2.31 kg), milk fat percent (ranged 3.55% to 3.68%), and milk yield (ranged 2.63 kg to 2.76 kg) of four groups were similar. Milk yield of 70% substituting group and control group were almost equal. Substituting 30% and 50% groups had numerical higher milk yield than control group (3.5% fat-corrected milk yield 2.82 kg vs. 2.69 kg, 5% increased). Income over feed cost was also promoted by 5 – 6%. In clusion from goat study, SSP could properly replace 30% to 70% of corn in diet. Replacing 30% to 50% made more profit. As a whole, feed formulation strategy of SSP needs to consider its anti-nutrient effect carefully. By substituting corn in diet is the more safe way for SSP re-utilization.
Goats and cows response to tomato pomace addition differently
Tomato pomace is the residue from ketchup or tomato juice processing. However, the high moisture content limits its transportation and preservation for feeds. To build up a friendly environment, the ensiling formula for tomato and its proper usage in diets for lactating goats and cows were studied. Tomato pomace and corn meal (TPC) were mixed at 10:1 fresh weight ratio and ensiled in big plastic bag. TPC had pH value of 3.71 and both dry matter and crude protein contents of 20%, respectively. A total of 20 heads of Saanen and Alpine goats were randomly assigned into four groups and raised in individual pens in a 28-d feeding trial. TPC silage was added into four treatment diets at 0, 6, 10 or 15% (DM basis) by substituting part of the distiller’s grains and corn in control diet. Results showed that four diets could support goats to have similar daily dry matter intake (1.91 to 2.03 kg), milk fat (avg. 4.32%), protein (avg. 3.20%), lactose (avg. 4.31%) and total solid (avg. 12.53%). Milk yield from goats fed 15% TPC silage diet was numerical lowered (2.34, 2.51, 2.58 and 2.24 kg). This trend was even obvious when expressed as 3.5% fat-corrected milk yield, 2.59, 2.78, 2.96, and 2.59 kg. In conclusion, tomato pomace could be well preserved when mixed with corn meal at 10:1 ratio. Diets supplemented with 6% to 10% tomato pomace+corn meal mixed silage improved the lactating performance of dairy goats and 10% inclusion was recommended (Fan et al., 2015).
However, when diets with 0 – 15% TPC silages were offered to Holstein cows, responses were different. Cows fed diets with TPC silage decreased their milk yield by 5%, decreased milk protein percent (Contrast statistic, P < 0.05) and increased milk urea nitrogen (P < 0.06, Table 6). Reason for the negative response was not known. Tomato pomace+corn meal silage is not a suitable feed for lactating Holstein cows shown in this study.
The level of by-products in diets
Many by-products have high amount of short fiber and high digestibility at the same time. This makes it possible to partially replace the long-fiber forage and also the high-starch grain mixture in diets. And this would contribute to decrease heat increment of forage when digested and avoid rumen acidosis problem when gain feeding is high. This characteristic is important for cows in Taiwan especially in hot and humid summer. In 2011, in our experiment dairy barn, the idea of high by-product 333 diet was applied. Diet for lactating cows were formulated to have 1/3 of forage, 1/3 of by-product, and 1/3 of grain mixture. From the rough comparison with the previous 2010 (diet contained about half forage and half grain) on milk yield performance, milk yield of all herd was improved, especially for the summer, from June to Sept. There was extra 3.8 kg milk per day per cow increased. It was postulated the 333 high by-product diet stimulated the feed intake and kept the healthier rumen.
To officially identify if the 333 diet could be used for lactating cows, a total of mid-production Holstein cows were randomly assigned into three diets including by-product at 10%, 20%, or 32% in dietary dry matter basis. By-products were common used wet brewer’s grains, sorghum distiller’s grains, soybean hull pellet, and wheat bran. Feeding trial lasted for 28 days and was replicated once. Results indicated that dry matter intake, milk yield, and milk efficiency were all similar for cows fed three levels of by-products. The performance was averaged 19.2 kg, 22.5 kg, and 1.17, respectively. Milk compositions and income over feed cost both were also not affected by by-product levels in diets (Table 7). These results implicated for mid-lactating Holstin cows diet formulated with 30% by-product was pretty acceptable.
To further understand the replacement influence of by-product to grain mixture, diets with fixed forage ratio 36% were designed to have control 333 diets, high by-product diets (37%, grain was cut to 27%), and high grain diets (37%, by-product was cut to 27%). Both high-producing Holstein cows and mid-producing Alpine goats were assigned in the replicate feeding trials. Results indicated all trait performances were similar among the three groups for both cows and goats (Table 8). By-products combined with wet brewer’s grains, sorghum distiller’s grains, soybean hull pellet, and wheat bran with high digestibility are of high feeding values. It is feasible to use them up to the high level 37% in diet and has no adverse influence (Lee et al., 2012; Fan et al., 2012).
MITIGATION OF GREENHOUSE GAS FROM RUMEN (RUSITEC STUDY)
Utilization of local feedstuff can reduce the carbon footprint of products, meats, milk, and eggs, from transpotation saving. Agricultural and food processing by-products proved to be valuable alternative feed resources for ruminants. Rumen is a big anaerobic fermentation tank that continuously produce high amount of methane. To reduce the global warming impact caused by ruminants the feed manipulation is thought to be one way of reducing the methane emission from rumen. The effect of adding by-products into diets on the methane emission were studied by means of the Rusitec (Rumen simulation techniques) system. Agricultural and food processing by-products, wet brewers grains, sorghum distillers grains, soybean hull pellet and wheat bran, were added into diets at 10%, 20% or 32% of dietary dry matter. Local corn silage, pangolagrass hay and low amount of imported alfalfa hay constituted the forage part and the other was corn-soybean grain mixture. Trial diets were fermented in the semi-continuous anaerobic fermentation system Rusitec for 10 to 12 days. Except the daily change of feed bag, fermentation gas was collected in gas bags and analyzed for methane and carbon dioxide by gas chromatograph. Results showed that the daily averaged pH values of fermentation liquid were 6.35, 6.34 and 6.30, and dry matter digestibility of three diets were 84.3%, 86.5% and 84.7% sequentially. Efficiencies of rumen microbial synthesis (g-microbe/g-organic matter disappearance) were tended to increase, 0.50, 0.55 and 0.58. Quantity of daily fermentation gases were 2.65, 2.53 and 2.50 L, respectively. The daily emission of methane and carbon dioxide reduced following the increasing proportion of by-products in diets (Table 9). Comparing 20% and 32% by-products with 10% by-products diets, daily output of methane could reduce by 9% and 22%, and for carbon dioxide 10% and 13% reached, respectively. From this Rusitec study, it is recommended the diet strategy of using higher level of local agricultural and food processing by-products is a beneficial way to reduce the greenhouse gas impact from ruminant raizing (Lee et al., 2016).
PROMOTINGTHE HEALTH OF WEANING GOATS
It is suggested the polysaccharides, triterpenoids, polyphenols, and flavonoids in mushroom might benefit the health of weaning goats. During the processing, shaping will cut off some bottom part of the mushroom. This bottom-off was estimated to have 1/10 of the whole mushroom weight, and resulted in about 7000 tons fresh weight a year. Effect of supplementation of mushroom bottom by-product in diets on growth performance and immune response of dairy goat kids around weaning period was evaluated. Mushroom off-bottom from Pleurotus eryngii and Flammulina velutipes were dried and ground. A total of 40 heads of 4-wk-old kids were randomly assigned into four groups for a 12-wk feeding trial. All kids received 150 g milk replaces in one liter per day until 8-wk-old. A corn-soybean meal basal diet was offered as the control group. Three supplemented groups were fed diets supplemented with 3% of Pleurotus eryngii, 3% of Flammulina velutipes, or the mixture of 1.5% Pleurotus eryngii and 1.5% Flammulina velutipes mushroom off-bottom. Feed and water were offered ad libitum. Growth performances and diarrhea index were measured. Results showed that kids fed four diets had similar feed intake and feed conversion rate. Supplementation of mushroom off-bottom increased the daily body weight gain, and kids fed the mixture diet achieved the higher gain compared with control group (P < 0.05, Table 10). Daily gains of kids in four groups were 146, 160, 165, and 173 g, respectively. Diarrhea index of kids showed the same trend that supplementation of mushroom off-bottom could decrease the occurrence of diarrhea. Diarrhea index decreased obviously (P < 0.05) of kids fed on the 3% Flammulina velutipes and the mixture mushrooms off-bottom diets during the 9th to 12th weeks of experimental period compared with control group. In conclusion, supplementation of the 1.5% of Pleurotus eryngii and 1.5% of Flammulina velutipes mushrooms off-bottom for goat kids is effective in improving their growth and health status (Shih et al., 2017).
CONCLUSION
For the past 15 years, global prices for feed ingredients and hay had increased sharply, causing higher production cost and food safety concern. Therefore, the need to explore available feed resources becomes more and more important. From our studies ensiling could be one economic way to preserve locally produced agricultural and food processing by-products as feeds for ruminants. Improving the feed values of some fibrous but high quantity residues is also an effective way to expand feed sources. Solid-state fermentation used in rice straw by spent mushroom substrate has shown great potential. Through the proper combination of by-products and the nutrition balance knowledge, all will influence the utilization of by-products. Note only the feed character, by-products could be helpful to livestock health and decreases the food mileage by means of lower methane emitted fom the rume. Fermented rice straw, pineapple pulp, spent mushroom substrate, sub-quality sweet potato, tomato pomace etc. all could be properly formulated into silage for feeding ruminants. More research work is needed. In the near future, we would like to try different sizes and formulas for by-products preserved as plastic wrapped round bales. It is believed that the diverse bale silage could promote the convenient transportation and hence set up the industry links, from production place to farms.
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