Effects Of Dietary Fiber On Growth Performance, Carcass Performance And Intestinal Physiology Of Finishing Pigs

This study was conducted to investigate the effects of different levels of crude fiber ongrowth performance, carcass performance, meat quality and intestinal physiology in finishingpigs. A total of60healthy crossed-bred (Duroc×Landrace×Yorkshine) finishing pigs withan average body weight of (51.45±7.98) kg were randomly allotted to3groups with4replicates per group and5pigs per replicate. Pigs were fed3diets, respectively, the dietarycrude fiber in diets were2.5%,7.5%and12.5%. According to the weight of finishing pigs,this experiment was divided into two phases:50～90kg and90～120kg. The experimentwas ended when the average body weight of pigs reached about120kg, then4pigs withsimilar weigh from every group were slaughtered.The results showed as follows: compared with the control group, the level of crude fiberincreased from2.5%to7.5%, F: G significantly decreased (P <0.05), ADG and ADFI had nosignificant difference in finishing pigs (P>0.05). When dietary fiber increased from2.5%to12.5%, ADG and ADFI (90-120kg) significantly decreased (P <0.05), F：G significantlyincreased (P <0.05). Compared with the control group, at the level of7.5%and12.5%massfraction of crude fiber, carcass oblique length and eye muscle area significantly increased (P<0.05), back fat thickness and suet ratio significantly decreased (P <0.05), in addition,dressing percentage decreased, but no significant difference was observed (P>0.05). At thelevel of7.5%and12.5%mass fraction of crude fiber, pH of longissimus muscle significantlydecreased (P <0.05), cooking loss significantly increased (P <0.05). When dietary fiberincreased from2.5%to7.5%and12.5%, the CP content of longissimus muscle significantlyincreased (P <0.05), in addition, the EE content significantly decreased in longissimusmuscle (P <0.05). Compared with the control group, pH of large intestine significantlydecreased (P <0.05), but there was no significant difference in pH of small intestine (P>0.05). Large intestine length, width and weight of experiment groups significantly increased(P <0.05), small intestine had no significant difference compared with the control group infinishing pigs (P>0.05). In addition, stomach percentage of body weight increased, but nosignificant difference was observed (P>0.05). To improve the diet fiber, VH of duodenumand ileum significantly decreased (P <0.05), CD of duodenum, jejunum, ileum and VH/CDof small intestinal significantly increased (P <0.05). In addition, acetate of samples fromcaecum significantly increased (P <0.05), propionate of samples significantly decreased (P < 0.05) and butyrate of samples decreased, but no significant difference was observed (P>0.05)compared with the control group.The result of this experiment indicated: compared with the control group, the level ofcrude fiber increased from2.5%to12.5%, carcass performance of finishing pigs improved tosome extent, however, growth performance and meat quality significantly decreased andwhich had a greater influence on the development of intestinal tract. But, at the level of7.5%mass fraction of crude fiber, carcass performance increased and there were no significantdifference in growth performance and meat quality.