Effects Of Feeding Programs On Meat Quality And Intestinal Microbiota Of Growing And Finishing Pigs

Pork is the main source of human to gain the animal protein,and China is a major pork producer and consumer,so it is very important to improve the quality of pork.The traditional pig producing process named as three-phase feeding（TPF）program divides the growth period into three stages by weight,and provides a single designated diet for each stage.However,nutritional need of pigs varies constantly,the TPF program can not provide nutrition that keep up with the new demands for animals.The daily-phase（DPF）feeding program uses two different feeds mixed in different ratios every day to prepare diets with different nutrition levels to better meet the nutritional requirements of pig growth.Previous research mainly focused on the effects of DPF on feed conversion efficiency,production costs,and nitrogen and phosphorus emissions,however,studies focus on pork quality was rarely reported.DPF changed the nutritional level of the diet,which is an important factor influencing the changes of intestinal microbiota and metabolic products.Therefore,the main purpose of this study is to explore the effect of DPF feeding method on the quality of growing fattening pork,and to study the intestinal microbiota and muscle metabolism including the differential changes of metabolites and metabolic pathways between the two feeding programs.In this experiment,240 eighty-day-old healthy pigs with similar body weight were selected and randomly divided into 2 groups with 8 repeats in each group and 15 pigs in each repeat.These pigs were feeded in the two different feeding methods until slaughter.The main test results are as follows:Experiment 1:Effects of daily-phase feeding on pork quality,antioxidant capacity and muscle fiber type.（1）Compared with the TPF group,the basic nutrients of the DPF group have no significant differences in water,crude protein,and intramuscular fat content（P>0.05）,and the sensory quality indicators of pork(meat color,p H_45min,p H_24h,drip loss,and shear force)were not significantly different（P>0.05）.（2）Compared with the TPF group,the catalase（CAT）,glutathione peroxidase（GSH-PX）and superoxide dismutase（SOD）activities in the DPF group were not significantly changed（P>0.05）with an increasing trend;the content of malondialdehyde（MDA）was reduced,but there were no significant difference（P>0.05）;the content of total antioxidant capacity（T-AOC）was significantly increased（P<0.05）.（3）Serological tests were performed on the TPF and DPF groups,and it was found that compared with the TPF group,the triglyceride（TG）content in the serum of the DPF group was significantly increased（P<0.05）,and the serum total cholesterol（TC）,high-density lipoprotein-cholesterol（HDL-C）,non-esterified fatty acid（NEFA）did not differ significantly（P>0.05）.（4）Morphological analysis was performed on the muscle HE staining of the TPF and DPF groups.The cross-sectional area of the muscle fibers in the DPF group was significantly lower than that in the TPF group（P<0.05）.（5）Examination of expression levels of muscle fiber typing related genes:Compared with the TPF group,the relative expression of My HCⅠm RNA in the DPF group was significantly increased（P<0.05）;there was no significant difference in the relative expression of My HCⅡa,My HCⅡb,and My HCⅡx m RNA.（P>0.05）.（6）Detection and expression of genes related to mitochondrial production found that compared with the TPF group,the relative expression levels of PGC1α,NRF1 and CPT1b m RNA in the DPF group were significantly increased（P<0.05）Experiment 2:Effects of daily-phase feeding methods on intestinal microorganisms and muscle metabolomes of growing and finishing pigs（1）Through analysis of 16S r DNA high-throughput sequencing of fecal microbiota in growing and finishing pig of TPF and DPF treatment groups,Firmicutes,Bacteroidetes,Proteobacteria,and Treponema Spirochaetes are common 4 dominant phylum.Proteobacteria is significantly different between DPF and TPF.Compared with TPF group,the Ruminococcus＿gnavus and Streptococcus＿equi were significantly reduced（P<0.05）,while lactobacillus（Lactobacillus＿agilis）in DPF group was increased;（2）Through analysis of muscle metabolomics,compared with the TPF group,the DPF treatment group promotes the AMPK-FOXO、PI3K-Akt-FOXO signaling pathway by up-regulating AMP,thereby promoting energy metabolism,lipid metabolism,and muscle antioxidant activity.ability.According to the above results,compared with the traditional three-phase feeding method,the daily-phase feeding method can significantly improve pork quality.Because muscle antioxidant capacity and type I muscle fiber content increased significantly.Daily-phase feeding can change the composition of intestinal microbiota and the changes of different metabolites and metabolic pathways.Lacobacillus＿agilis can be used as candidate differential microorganisms.AMPK-FOXO、PI3K-Akt-FOXO can be used as a specific metabolic pathway on the mechanism of improving pork quality by daily-phase feeding.