| This experiment was conducted to study the effects of different diets on growth performance,slaughter performance,blood indices,rumen microbial composition and diversity of fattened lambs under house feeding condition,and to provide technical reference for fattening Hulunbuir lambs and production of high-quality Hulunbuir mutton.Healthy and disease-free Hulunbuir lambs of similar weight were randomly divided into two groups according to their weight.There were 15 lambs in each group.And each group of lambs were fed different daily ration.The control group fed with local home-made concentrate and alfalfa,and the experimental group was fed with "361","362" produced by Inner Mongolia Bayinnaoer Pu Ai more feed Co.,Ltd,which was committed to produce feed by Animal Nutrition Team of Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences.The trial period was 115 days.The pre-feeding period was 15 days and the formal period was 100 days.This trial was conducted from September 10,2021 to January 4,2022 at the Grass and Pasture Experiment Station of Ewenk Autonomous Region.1.Effects of pellets on growth performance of fattening lambs: The test began to record daily intake and weighing the lambs every 20 days during the fattening period,calculating the feed to meat ratio and the average daily gain,and collecting manure samples and diets to determine the apparent digestibility of nutrients and analyze economic benefits.The results showed that the weight of lambs in the test group was higher than that of the control group throughout the test,especially in the 21-40 d,41-60 d and 81-100 d of the fattening period(P<0.05).The average daily gain of lambs in the test group was significantly higher than that of the control group in the 21-40 d and 41-60 d of the fattening period(P<0.05).The feed to meat ratio of lambs in the test group was better than that of the control group,especially at 21-40 d and 41-60 d of the fattening period(P<0.05).The apparent digestibility of CP and NDF of the test group was significantly higher than that of the control group(P<0.05).The fattening benefit of lambs in the test group was increased by 57.80 RMB per lamb compared with the control group.2.Effects of pellets on slaughter performance of fattening lambs: At the end of the test,5 lambs in each group were randomly selected and slaughtered after fasting for 24 h fasting and 2h water fasting,and slaughter performance indexes were measured.The test results showed that the pre-slaughter live weight,carcass weight and slaughter rate of lambs in the test group were significantly higher than those in control group(P<0.05).3.Effects of pellets on blood biochemical indexes and immune indexes of fattening lambs: During the test,5 lambs in each group were selected.Blood samples of these lambs were collected on the 40 th,80th and 115 th day of the test,and serum was separated,then extracted for the determination of blood physical and chemical indexes and immune indexes.The results showed that the concentration of CPK in the blood of lambs in the test group decreased compared with that in the control group at the 40 th day of the test,while the concentration of s CD8 increased significantly(P<0.05);The concentration of IL-1 in the test group decreased significantly compared with that in the control group at the 80 th and 115 th day of the test(P<0.05).And the concentration of s CD4 in the test group was significantly lower than that in the control group at the 80 th day of the test(P<0.05).In the meantime,the AKP concentration in the blood of lambs in the test group was strikingly lower(P<0.05)compared with the control group at 40 th day.The HDL and LDL concentrations in the blood of lambs in the test group were vastly lower(P<0.05)compared with the control group at 80 day.4.Effect of pellets on rumen microflora of fattening lambs: At 115 th day of the trial,5lambs were randomly selected from both groups and the rumen fluid bacteria of the test animals were sequenced by 16 S r RNA amplicon sequencing technology.The results showed that at the phylum level,feeding the new composite pellet resulted in a high reduction in the abundance of Elusimicrobiota in the rumen of lambs compared to the control group(P<0.01).At the genus level,feeding the new composite pellet resulted in a high decrease(P<0.01)in the abundance of Elusimicrobium;Lachnospiraceae and Bacteroiales(P<0.05)in the rumen of lambs,while the beneficial genera Prevotella and Veronococcus(P<0.05)were significantly reduced.Prevotella and Veillonellaceae(P<0.05).It was shown that feeding pellets promoted the growth of fiber-degrading bacteria in the rumen and enabled the lambs to consume nutrients from the ration more efficiently. |
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