Effects Of Dietary Fiber Levels On Growth Performance And Meat Quality Of Different Genetically Based Finishing Pigs

In this study,fermented corn stalks(FCS)was used as the experimental dietary fiber source to replace the basic diet as a whole,and to study the effects of dietary fiber level on the production performance,nutrient digestibility and meat quality in different genetic and physiological stages of pigs.This study provides experimental basis for interaction between dietary fiber levels and different genetic bases.A total of 96 healthy Songliao black(SLB)pigs and Duroc×Landrace×Yorkshire(DLY)hybrid pigs with body weight of(60.52±4.59)kg,randomly the two breeds of pigs were divided into 4 groups,each group consisting of 3 replicates;Songliao black pig group: SA,SB,SC,SD;and the DLY pigs group as: DA,DB,DC,DD.The control groups were SF0 and DF0,and the dietary crude fiber level of the basal diet was 2.82%.represents the experimental groups as SB and DB,SC and DC,SD and DD,and the dietary crude fiber levels were 4.82%,6.86%,and 9.01%.The two breeds of pigs were slaughtered at a body weight gain of 90kg(Fattening stage 1)and 120kg(Fattening stage 2)(Total slaughter 48)for a total test period of 80d(40d + 40d).The growth performance,carcass traits,nutrient digestibility,intestinal physiology and meat quality were determined for the two fattening stages.The results show:In terms of growth performance.1)Compared with DLY pigs,the daily gain and daily feed intake of SLB pigs were lower(P<0.05)when the dietary crude fiber level was 4.82% and the average daily gain of SLB pigs and DLY pigs was the highest when the dietary crude fiber level was 9.01%.The average daily gain of SLB pigs is higher than DLY pigs.2)Compared with DLY pigs,the SLB pigs have high back thickness and low skin thickness.Compared to both SLB pigs and DLY pigs,the control group had thicker back and skin thickness than the experimental group.3)Compared with the SLB pigs and DLY pigs,the serum LDL-CH,GLU,BUN and TP levels were lower when dietary crude fiber levels were 4.82% and 6.86%.However,the SLB and DLY pigs recorded the lowest serum GLU.In terms of nutrient digestibility and intestinal physiology 1)Compared with DLY pigs,SLB pigs had lower EE digestibility however,with higher CF,NDF and ADF digestibility.The digestibility of DM,CF,NDA and ADF in finishing pigs decreased with increasing dietary fiber levels.The digestibility CP in the SLB pigs and DLY pigs was higher at dietary fiber levels of 4.82% and 6.86%.Meanwhile,the SLB pigs maintained a high nutrient digestibility when the dietary crude fiber level was 9.01%.2)Compared with DLY pigs,the SLB pigs had higher propionic acid content(P<0.05)and lower n-butyric acid content(P<0.05).At the second stage of fattening,the content of propionic acid and total VFA level was lower(P<0.05);SLB pigs and DLY pigs increased the fermentation of microorganisms in the cecum and the volatile fatty acid content when the crude fiber level of the diet was 4.82%.The total content of the cecal VFA contents in the SLB pigs at the 9.01% of dietary fiber level was higher than DLY pigs.(3)Compared with DLY pigs,the SLB pigs had a duodenal villus height and a low ratio of velvet glands(P<0.05),and a high jejunum villus height(P<0.05).The depth of intestinal crypt was high(P<0.05),and the height of the jejunum was high(P<0.05).The ratio of the duodenal velvet gland in SLB pigs increased with the increase in dietary fiber level in the fattening stage 1;the jejunum gland ratio of the fattening stage 2 test group was higher than that of the control group;the DLY pigs duodenal velvet gland in the diet,the crude fiber level was 4.82% highest.In terms of meat quality 1)Compared with DLY pigs,the SLB pigs had higher muscle redness(P<0.05)and lower drip loss(P<0.05).At the second stage of fattening,muscle brightness and shear force were higher(P<0.05)and the drip loss was low(P>0.05).The SLB and DLY pigs had lower drip loss and muscle shear at a dietary fiber level of 4.82%,with a higher pH value.2)Compared with DLY pigs,the SLB pigs had high crude protein and crude fat level in the fattening stage(P<0.05).The crude protein,crude fat and dry matter content in the second stage of fattening were higher(P>0.05).The SLB and DLY pigs have higher muscle fat content when the dietary crude fiber level was 4.82%.3)Compared with SLB pigs,the DLY pigs muscle C16:0 content in the fattening stage 1 was low(P<0.05),C18:1n9 content was high in the fattening stage 2,muscle C16:0,C18:0,C18:2n6.The contents of SFA and PUFA were higher(P<0.05),and the contents of C18:1n9 and MUFA were lower(P<0.05).With the increase of dietary fiber level,the SFA level in SLB and DLY pigs muscles decreased.The SLB pigs muscle PUFA was highest when the dietary crude fiber level was 4.82%,DLY pigs muscle PUFA increased with increasing dietary fiber levels.The above results indicated that dietary fiber levels have a certain effect on SLB and DLY pigs.When the dietary crude fiber level was 4.82%,the average daily gain of SLB and DLY pigs increased to some extent.SLB pigs can maintain high production performance under high dietary fiber,increasing the dietary fiber level has no adverse effects on the slaughter performance and intestinal morphology of finishing pigs,and can improve nutrient digestibility and cecal fermentation function to a certain extent.Increasing dietary fiber levels has an effect on muscle quality,muscle nutrients and muscle fatty acid composition.In summary: SLB and DLY pigs have significant differences in production performance,slaughter performance,digestion efficiency of nutrients,intestinal physiology and meat quality.Dietary fiber levels have a significant interaction with genetic basis.The dietary fiber level was matched to the genetic basis to ensure optimal performance and meat quality in the pig.