The Effects Of Hemp Toppings On Growth Performance,Rumen Environment And Blood Metabonomics In Xiangdong Black Goats

The purpose of this study was to investigate the effects of hemp toppings on growth performance,meat quality,rumen environment,rumen microflora and blood metabonomics in Xiangdong black goats,which would lay a foundation for unconventional forage development in South China.A total of 40 Xiangdong black goats with weight of(7.82±0.57)kg in good health were selected,which were divided into four groups by random single factor design.Four groups included control group,test group Ⅰ(MF),test group Ⅱ(MT)and test group Ⅲ(ME),with each group of 10 repeat.Control group was fed based diet,and the other three groups were fed with 5%10%and 20%respectively of hemp toppings equivalent substitute alfalfa hay.The trial period was 74 days,which the first 10 days for adaptation.The overall study consists of the following three parts1 Effects of hemp toppings on growth performance,visceral index and muscle quality of black goatsAverage daily gain,average daily feed intake and feed/gain ratio were recorded during the experiment.At the end of the experiment,carcass weight was calculated,visceral organs were taken to measure visceral index,and longissimus dorsi muscle was taken to measure muscle quality.Results show that:1.The addition of hemp toppings had no significant effect on the average daily gain,slaughter rate and muscle quality of black goats(P>0.05).2.The average daily feed intake of black goats was significantly decreased(P<0.05),and the ratio of feed to gain was significantly decreased(P<0.05).3.The liver index of black goats in experimental group was increased by adding hemp toppings(P=0.068),kidney index was significantly increased(P<0.05).4.No THC were detected in the experimental group of Black goats.In conclusion,adding proper amount of hemp toppings to the diet can promote the organ development,reduce feed consumption and improve production efficiency to a certain extent.2 Effects of hemp toppings on rumen environment of black goatsAfter slaughter,10 mL of rumen juice and rumen chyme were collected and stored in liquid nitrogen and-80 to determine the pH of rumen environment,ammonia nitrogen volatile fatty acids and rumen microbial indexes.Results show that:1.There were no significant effects of hemp toppings on rumen pH(P>0.05),hemp toppings significantly increased the ammonia-nitrogen content in rumen(P<0.05).2.Compared with the control group,the contents of total volatile fatty acids in the three experimental groups were significantly increased(P<0.05),and the proportions of acetic acid and butyric acid were significantly increased(P<0.05).3.There were no significant effects of hemp toppings on rumen microbial species and abundance(P>0.05).The microbial composition of each group was similar.Bacteroidetes and Firmicutes accounted for the highest levels of phylum and Prevotella was the highest level in genu.In conclusion,hemp toppings had no effect on rumen microbial community,and can increase the content of volatile fatty acids in rumen,adjust the proportion of volatile fatty acids,and provide more energy for the growth and development of ruminants.3 Effects of hemp toppings on blood metabolism of black goatsGoats vein blood was drawn on an empty stomach in the morning of the sampling day,and the serum was extracted by centrifugation at 1000×g for 15 min.The serum was quickly placed in-80℃ for cryoprecipation,and the non-targeted metabolomic determination was performed.Based on LC-MS metabolomics,410 metabolites were obtained after screen(VIP>1.0;P<0.05),which included 5,10-Methylene-THF,Dihydrofolic acid,folate,Betaine,Ectoine and all-trans-Retinoic acid.It mainly involves glycine,serine and threonine metabolism,folate-carbon pool,steroid hormone metabolism,Retinol metabolism and some carcinogenic pathways.In conclusion,the dietary addition of hemp toppings can increase the organ index,improve the growth performance,reduce the feed to gain ratio and increase the economic benefit of black goats.Feeding hemp toppings does not produce THC residue in the body of black goats,and has no effect on the muscle quality of black goats,which meets the needs of safe production.Hemp toppings increased the content of volatile fatty acids in the rumen,provided more energy for the growth and development of black goats,and had no negative effect on the rumen microbial community.Hemp toppings is involved in various metabolic pathways such as amino acid metabolism,energy metabolism and hormone metabolism of black goats.By adjusting the levels of relevant differential metabolites in the metabolic pathways,it can improve the growth performance and immune ability of black goats,and reduce the probability of tumor and cancer occurrence.