| In order to alleviate the adverse effects of early weaning stress on the growth of lambs.The effects of sodium butyrate on growth performance,gastrointestinal tract development and intestinal microorganisms of weaned lambs were studied.It provides a theoretical basis for the application of sodium butyrate in lamb production.Twenty four weaned lambs of 42 days old were randomly divided into four groups,each group had six repetitions.The blank control group was fed with basic diet,the antibiotic group were supplemented 250 mg/kg Flavomycin in basic diet,the sodium butyrate A group and B group were supplemented 2 g/kg and 3 g/kg sodium butyrate in basic diet respectively.On the 14 th and 28 th day of the experiment,three lambs in each group were slaughtered and sampled.The results were as follows:(1)Effects of sodium butyrate on growth performance,apparent nutrient digestibility and slaughter performance of weaned lambsGrowth performance: on the 14 th day,the average daily gain of sodium butyrate A and B group were significantly higher than that of the blank control group(P< 0.05),and the feed/weight ratio was significantly lower than that of the blank control group(P<0.05).On the28 th day,the average daily intake of sodium butyrate group A and B were significantly higher than that of the blank control group(P<0.05).Apparent digestibility of nutrients: on the 14 th day,the digestibility of dry matter in sodium butyrate A group was significantly higher than that in the control group(P<0.05).The digestibility of crude protein in sodium butyrate B group was significantly higher than that in the blank control group(P<0.05).On the 28 th day,the digestibility of dry matter,crude protein and neutral degergent fiber in sodium butyrate A group was significantly higher than that in the blank control group(P<0.05).The digestibility of crude protein in sodium butyrate B group was significantly higher than that in the blank control group(P<0.05).Slaughter performance: sodium butyrate had no significant effect on the final weight,carcass weight and slaughter rate of weaned lambs(P>0.05).(2)Effect of sodium butyrate on gastrointestinal development of weaned lambsSodium butyrate had no significant effect on rumen relative weight(volume)(P>0.05).On the 14 th day,sodium butyrate had no significant effect on rumen and small intestine morphology(P>0.05).On the 28 th day,the thickness of rumen dorsal capsule and the height of rumen papillain sodium butyrate A group and sodium butyrate B group were significantly higher than those in the blank control group(P<0.05).The thickness of rumen abdominal capsule in sodium butyrate B group was significantly higher than that in the blank control group(P<0.05).The height of villi in duodenum,jejunum and ileum,the surface area of villi in jejunum and the ratio of villi height to crypt depth in jejunum and ileum in sodium butyrate group B were significantly higher than those in the control group(P<0.05).The expression of EGF m RNA in duodenum and IGF-?R m RNA in jejunum in sodium butyrate A group was significantly higher than that in blank control group(P<0.05);the expression of GCG m RNA and GLP-2R m RNA in duodenum and IGF-? and GCG m RNA in jejunum of sodium butyrate B group were significantly higher than that in blank control group(P<0.05).(3)Effect of sodium butyrate on intestinal microorganism of weaned lambsThere was no significant effect of sodium butyrate on the alpha diversity of intestinal microorganisms in lambs(P>0.05).The PLS-DA analysis showed that there were significant differences in microbial structure between sodium butyrate A group,sodium butyrate B group and blank control group,and in cecum and colon,there were significant differences in microbial structure between sodium butyrate A group and sodium butyrate B group.In jejunum and ileum,the microbial structure of sodium butyrate group B was similar to that of antibiotic group.The composition analysis of phylum level showed that the composition structure was similar of four groups.The composition analysis of genus level showed that the composition and proportion of microbial structure in sodium butyrate A and B groups were different from those in the blank control group,and there was no similarity between the two groups.The analysis of Venn diagram showed that the species number and uniqueness of sodium butyrate group A was the highest.In conclusion,both 2 g/kg sodium butyrate coated and 3 g/kg sodium butyrate coated can improve the growth of weaned lambs,promote the morphological development of gastrointestinal tract,improve the apparent digestibility of nutrients,stimulate the expression of genes related to intestinal development,and regulate the intestinal microflora.However,the 2g/kg sodium butyrate coated group could enrich the structure and composition of microorganisms in the intestine of weaned lambs,so it is recommended to add 2 g/kg sodium butyrate coated. |
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