| With the increasing scale and intensive degree of beef cattle production,the consumption of feed by beef cattle has also increased.According to reports,the feed cost of the cattle farm accounts for 70%～80% of the feeding cost.The quality of feeding will not only affect the cost of animal feeding,but it is more likely to have an adverse effect on the health and growth performance of the animal.How to “return to the field” to make better use of straw and agricultural and sideline product waste,reduce feeding costs,and improve economic efficiency is a permanent research topic for beef cattle production.Fresh brewer’s grains are often used in beef cattle production because of their low price and rich in nutrients such as protein and fiber.However,the moisture content of WBG is as high as 70%-80%,it is easy to spoil and deteriorate in summer,and it is cold and hard in winter.The problem of using in beef cattle production practice still needs to be improved.This experiment intends to select Jinjiang cattle as the research object,to explore the effects of winter feeding WBG diets on Jinjiang cattle production performance,and explore winter feeding from the aspects of rumen bacteria,intestinal morphology,gastrointestinal hormones,hypothalamic feeding regulation and brain-gut axis The reason why WBG diet affects the daily weight gain of Jinjiang cattle provides a theoretical basis for the regulation mechanism of beef cattle intake.This test is divided into the following three parts:1 Effects of environmental temperature on feed intake of Jinjiang cattle and relative expression of rumen bacteria with different augmentation in winterIn order to explore the effect of environmental temperature on the feed intake of Jinjiang cattle and the relative expression of different augmented rumen bacteria,18 Jinjiang bulls weighing 311.17±18.04 kg were selected for free intake of a diet containing 75% wet brewer’s grains.Among them,the winter fattening experiment was 44 days,and it was found that the average daily gain was significantly reduced.The average daily gain was 2standard deviations as the boundary group 4 heads 602.27±61.89 g/d are group H,and 2heads 79.55±11.36 g/d are group L.After venous blood sampling,they were slaughtered,and the rumen contents and hypothalamus organization were collected.Measure the relative expression of rumen bacteria,blood amino acid and neurotransmitter content,and expression of appetite-related feeding genes.The results showed that:(1)the feed intake decreased at low temperature,and the dry matter intake of distiller’s grains increased;(2)the rumen bacteria Bacteroides phylum decreased,the ratio of Bacteroides/ Firmicutes phylum decreased,the total bacteria,Rumenobacter amylovora and Streptococcus bovis were significantly reduced(P<0.05),and filamentous bacillus succinate and Vibrio cellulolyticus had a decreasing trend.To sum up,it can be seen that feeding WBG in winter can reduce the cattle population’s feed intake,and individuals with high weight gain have a higher abundance of rumen protein and cellulose-degrading bacteria,which is due to the a strong adaptive for WBG.2 Differences in intestinal morphology,digestive enzyme activities and gastrointestinal hormones of Jinjiang cattle with different weight gains in winter.The purpose of this study was to study the mechanism of reducing Jinjiang cattle’s weight gain by feeding brewer’s grains in winter from the intestinal point of view.The experiment grouping and design are the same as before.On the day of the end of the experiment,blood was collected from the vein and then killed.Collect intestinal tissue and chyme.The reasons for weight loss of Jinjiang cattle were discussed from three aspects:intestinal morphology,chyme digestive enzyme activity and gastrointestinal hormone content.The results showed that:(1)The height of duodenal villi of Jinjiang cattle in group H was significantly higher than that in group L(P<0.05),and VH/CD was significantly higher than that in group L(P<0.05);(2)and duodenopancreatic Protease and lipase activity,jejunal amylase activity,trypsin activity and lipase activity were significantly higher than those of group L(P<0.05).Group H Jinjiang cattle duodenal amylase activity and ileal lipase activity were higher than group L(0.05<P<0.1);(3)The blood gastrointestinal hormones CCK and GIP have a decreasing trend(0.05<P<0.1),and SS has an increasing trend(0.05<P<0.1).In summary,Jinjiang cattle with high weight gain have higher duodenal villi height,more protease and lipase activities,and lower gastrointestinal hormone content,which makes the intestinal digestion and absorption of WBG stronger.3 Differences in brain-gut axis pathways of Jinjiang cattle with different weight gains in winter.The purpose of this experiment is to explore the reason for the different gain weight of Jinjiang cattle from the perspective of the brain-gut axis in winter and the supply of beer lees.The grouping and design of the experiment are the same as before.On the day of the experiment,blood was collected from the vein and then killed.The reasons for the low weight gain of Jinjiang cattle were explored from three aspects: blood amino acid concentration,neurotransmitter content and hypothalamic feeding genes.The results showed that:(1)The blood amino acid tryptophan concentration of Jinjiang cattle in group L increased significantly(P<0.05);the blood tyrosine concentration tended to increase;(2)Hypothalamic nerve factor 5-HT and dopamine concentration Significant increase(P<0.05),the concentration of brain-derived neurofactor BDNF tends to increase,the concentration of5-HT and brain-derived neurofactor BDNF in the blood increases significantly,and the concentration of dopamine is extremely significant(P<0.01);(3)The m RNA expression level of the hypothalamic appetite enhancing gene Ag RP in the L group was significantly reduced(P<0.05).In short,the reason why Jinjiang cattle with low gain weight is supplied with cold and wet beer lees in winter may be due to the increased blood tryptophan content,which acts on the hypothalamus through the brain-gut axis pathway,which significantly down-regulates hypothalamic feeding Expression of the gene Ag RP and reduce intake. |
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