Evaluation Of Nutritive Value And Effects Of Bacterial Protein On Performance,Intestinal Tract Physiology In Broiler Chickens

In order to exploit and better use of the bacterial protein(BP)-a by-product from the production of feed grade lysine,three trials were done to evaluate the nutritive value and effects of BP on the growth performance,intestinal tract physiology in broiler chickens. Trial 1 was the analysis of general nutrients of BP.The crude protein content(79%) was very high,while the true protein(50%) and amino acid(47.55%) with very high non-protein nitrogen.There were 8.6%nucleic acid and 10%(NH4)2SO4.Tial 2 was the evaluation of nutritive value of BP and feeding effects in broiler chickens on basis of equal protein to substitute the soybean meal(SBM) with or without the addition of amino acids according to the total amino acids contents.1400 Cobb broiler chickens were randomly assigned to five groups with 7 replicates of 40 birds.Group 1 was basal diet;Group 2 and 3 were BP diets with 20%and 40%protein substitution of soybean protein in basal diet; Group 4 and 5 were the BP diets with the addition of Lys,Met or Cys in the diets of group 2 and 3 according to the total amino acid level of group 1.The availability of protein or amino acids in diets or BP were evaluated by total feces collection method or TME method respectively.The birds were fed in cage and free access to feed and water.The results showed that:①Average body weight(ABW) and average daily feed intake(ADFI) of group 2 and 4 were the highest in all groups.Gain:feed of group3 and 5 was significantly different with those of the other groups(P＜0.01);②The indexes of digestive organ in group3 was significantly higher than the other groups(P＜0.05);③There were no significant difference in dressing percentage,breast muscle ratio,leg muscle rate among the groups;④Differences of intestinal tract pH were significant among all the groups (P＜0.01);⑤The protein availability,amino acid apparent and true availability of group 1, 2 and 4 were significantly higher than those of group 3 and 5(P＜0.01);⑥Total amino acid apparent and true availability of BP were 52.2%and 57.96%respectively.Tiral 3 was to study the effects of bacterial protein on performance,intestinal tract physiology in broiler chickens on the basis of available amino acids with or without acidifier.750 one-day-old Avain broiler chickens were randomly assigned to five groups with 10 replicates of 15 birds.Group 1 was basal diet;Group 2 or 3 were 4%or 8%BP to substitute the same protein from SBM in diets.Group 4 and 5 were added 0.2%acidifier in group 2 or 3.The birds were fed in cage and free access to feed and water.The results showed that:①ABW and ADFI of group 1,2 and 4 were higher,while Gain:feed of group1,2 and 4 was lower than those of group 3 and 5(P＜0.01);②Blood ammonia,ileum ammonia and ileum pH of group3 were the highest in all of the groups(P＜0.01);③Ileum villi length of 22d broilers in group 3 was significantly higher and was lowest in 43 day in all groups(P＜0.05).Ileum crypt depth in 22 d broilers in group 5,3 was higher than that of in group 2 and 4.④Intestinal mucosa protein of 43d broilers in group3 and 5 were lower significantly than the other groups(P＜0.01);⑤Intestinal DNA/RNA of group 2 and 3 was lower than that of other groups(P＜0.01).In conclusion,the crude protein of BP was very high,but the true protein,amino acids contents and availability were low with a lot of non-protein nitrogen.With the substitution of 20%SBM protein or 4%in diet,the broiler growth performance did not influence,but decreased with the substitution of 40% SBM protein or 8%in diet.The intestine or blood ammonia or pH,or the turnover of intestine mucosa were increased with the addition of BP.The feeding value of BP could be improved by the addition of amino acids based on total or available amino acid and acidfier.