Effects Of Bamboo Vinegar Powder On Production Performance, Immune Function And Intestinal Microflora Community Of Weaned Piglets

Seeking ecological and green growth-enhancing feed additive in pig production is one of research focuses in animal nutrition field. The aim of this study is to explore the main chemical components of bamboo vinegar powder and its effects on production performance, diarrhea index, small intestinal histology, blood physiological and biochemical indexes, immunity-related genes’expression and intestinal microflora community of weaned piglets. Forty-five crossbred(Duroc×Landrace×Yorkshire) weaned piglets (all male and castrated, body weight 6.74±0.17kg) at 31 days of age were randomly assigned to 5 treatments according to live weight with 3 replicates(pens) per treatment and 3 piglets in each pen. The 5 treatments were as follows: CON (a basal diet), ANT (the basal diet+0.12%compounding antibiotics i.e.10% Bacitracin zinc at 0.008%,10% Colistin at 0.004%,10% Roxarsone at 0.01% and carrier), BV1 (the basal diet+0.1%bamboo vinegar powder), BV5 (the basal diet+0.5%bamboo vinegar powder), BV10 (the basal diet+1.0%bamboo vinegar powder). The experiment lasted 35 days, of which 31days-53days at age was earlier stage and 53days-66days at age was later stage. This study consisted of the following four parts.1. Effects of bamboo vinegar powder on production performance and diarrhea of weaned piglets based on component analysisGas chromatography-mass spectrography (GC-MS) was applied to test the major components of bamboo vinegar powder. Average daily gain (ADG), average daily feed intake (ADFI), the ratio of feed/gain (F/G), diarrhea rate and diarrhea score were recorded and calculated during the experiment. At the end, the related organ index and pH of gastric and small intestinal content were tested. The results indicated:(1) The major components of bamboo vinegar powder could be divided into phenols, aldehydes, organic acids, ketones and heterocyclic compounds. (2)During earlier stage, ADG of BV1 and BV 10 tended to increase compared with CON (P<0.1) and ADG of BV5 was significantly higher that of CON (P<0.05); F/G of BV5 tended to decrease compared with CON (P<0.1). (3) During later stage, diarrhea rate and diarrhea score of ANT, BV1, BV5 were significantly lower than that of CON (P<0.05) and these of BV5 were the lowest.(4)pH of gastric juice of BV5 was 46%lower than CON (P<0.1) and that of BV5 was significantly decreased compared with ANT (P<0.05).2. Effects of bamboo vinegar powder on small intestinal histology of weaned pigletsSmall intestinal segments were sampled to make into paraffin sections to observe histologic indexes. The results showed that bamboo vinegar powder added in weaned piglets’ diets significantly decreased crypt depths of small intestinal segments (P<0.05) and significantly increased the ratio of villus height to crypt depth (P<0.05). The ratio of villus height to crypt depth of jejunum and ileum of BV5 was optimum among the treatments. The villus height of jejunum and ileum in bamboo vinegar powder experimental groups also tended to increase (P<0.1). Intestinal villuses of piglets in BV1, BV5 and BV10 were more inerratic and tidier than those in CON and ANT. Besides, the crypts of the former ones were shallower. These proved that intestinal histology of piglets in bamboo vinegar powder experimental groups were regulated and the dosage at 0.5% showed optimum regulatory effects.3. Effects of bamboo vinegar powder on blood physiological and biochemical indexes and immunity-related genes’ expression of weaned pigletsThe blood was sampled from precaval vein to test physiological, biochemical and anti-oxidation and immune indexes at 53 and 66 days at age. Real-time PCR was applied to evaluate the mRNA expression levels of TNF-α, IL-1β and IL-6 in liver, spleen, duodenum, mesenteric lymph nodes. The results were as follows:(1) White blood counts (WBC) of ANT, BV1 at 66days at age were significantly decreased compared with CON (P<0.05) while WBC of BV5 at 66days at age had no significant difference from that of CON (P>0.05). Compared with CON, hematocrit of ANT, BV10 at 53days at age were significantly increased (P<0.05); Red cell distribution width-SD of BV5 at 66days at age was dramatically decreased (P<0.05); Blood platelet count of BV1 at 66days at age was significantly increased (P<0.05). (2) Serum alanine transaminase of BV5 at 53 days at age was dramatically lower than that of ANT (P<0.05). Compared with CON, albumin of ANT, BV5 at 53 days at age were significantly decreased (P<0.05); Alkaline phosphatase of ANT, BV10 at 66days at age were significantly increased (P<0.05). (3) Bamboo vinegar powder significantly enhanced glutathione peroxidase, which is antioxidant index (P<0.05). (4) TNF-α, IL-1β and IL-6 mRNA expression levels in duodenum of bamboo vinegar powder treatment groups tended to lower (P<0.1) and IL-6 mRNA expression levels in spleen of these groups were significantly lower than ANT (P<0.05). TNF-α and IL-1β mRNA expression levels in liver of BV5 were significantly raised (P<0.05). TNF-α, IL-6 mRNA expression levels in mesenteric lymph nodes of BV10 were significantly lower (P<0.05). These indicated that bamboo vinegar powder had regulatory effects on blood physiologic and biochemical parameters and immune function of weaned piglets.4. Effects of bamboo vinegar powder on intestinal micro flora community of weaned piglets Colonic content of piglet was sampled for this experiment at 66 days at age. Highthroughput 16S rRNA sequencing technology was applied to evaluate effects of bamboo vinegar powder on intestinal microflora community of weaned piglets. The results manifested:(1) Diversity indexes of intestinal microflora, namely operational taxonomic unit (OTU), chao1 index and shannon index of ANT and BV1 were significantly higher than CON (P<0.05). Those three indexes of BV5 and BV10 were also higher than CON. (2)Bamboo vinegar powder could regulate composition of intestinal microflora of weaned piglets and form unique intestinal microbial community structure. Community structures of BV5 and BV10 were more dramatically different from CON, which formed distinct cluster in hierarchical dendrogram. Specifically, bamboo vinegar powder could promote the proportion of commensal bacteria including Prevotella, Phascolarctobacterium and Blautia while reduce the proportion of pathogenic bacteria such as the infectious bacteria in Streptococcus category. In summary, bamboo vinegar powder exerted regulatory effects on intestinal microflora of weaned piglets, and its production-enhancing mechanism might be related with this.Based on the results above, bamboo vinegar powder could promote growth performance while reduce diarrhea of weaned piglets. Its mechanism might be related with the regulatory effects on immunity-related genes’ expression and intestinal microflora. Appropriate dosage of bamboo vinegar powder in diet was 0.5%.