Effects of Lactiplantibacillus Plantarum fermented feed on meat quality and lipid metabolism of broilers.

The study aimed to investigate the impact of single-bacteria and compound-bacteria fermentation on chemical composition and metabolite profiles of feeds, and further explore the effects of single-bacteria fermented feed (DF) and compound-bacteria fermented feed (FF) on the growth performance, meat quality, and lipid metabolism of broilers. A total of 192 broilers were randomly assigned to three treatment groups. Broilers in the three treatment groups were fed corn-soybean meal basal diets with 3 % non-fermented substrate (CON), 3 % DF, and 3 % FF, respectively. Results showed that fermentation significantly reduced the pH value and increased the crude protein content of feed (P < 0.05). Metabolomic results showed distinct metabolite profiles among unfermented feed, DF, and FF, suggesting that fermentation changed the metabolite composition of feed. Additionally, compared with unfermented feed, the abundance of short peptides (Arg-Gln-Tyr-Lys, Leu-Pro-Thr, and Tyr-Glu-Asn) and organic acids (lactic acid and caffeic acid) significantly increased in DF and FF, while the abundance of anti-nutritional factors (cupreine, ergocornine, and veratridine) significantly decreased. The results of the broiler farming experiment showed that DF and FF increased the average daily gain of broilers at d 7 (P < 0.05). Moreover, DF decreased the shear force of breast meat, while it increased the intramuscular fat content relative to CON (P < 0.05). In addition, DF and FF significantly reduced the abdominal fat weight, liver triglycerides and total cholesterol content, and serum triglycerides level. DF and FF also significantly reduced the expression level of genes that promote lipid synthesis, and increased the expression level of genes that promote lipolysis in both abdominal fat and liver. These results indicated that DF and FF could reduce fat deposition in broilers without affecting growth performance. The overall effect of DF on fat deposition in broilers was superior to that of FF.