| Single factor design was adopted in our experiment. Nine hundred of PlymouthRock Chickens of the same batch and similar weight were allocated into three groupswith three replications in each group and one hundred of chicken per replication. Asthe control group, chicks in control group were fed with basal diet. Chicks in ABP andABPY groups were fed with basal diet supplemented respectively with ABP andABPY. The experiment started following one-week pre-feeding for a trial period ofninety days. We aimed to decipher the impact of antimicrobial peptide on productionperformance, slaughter performance, breast muscle quality and nutrient componentsof Plymouth Rock Chickens. Meanwhile, expression of H-FABP mRNA was detectedby the real-time quantitative PCR to investigate the mechanism of the effect ofantimicrobial peptide on breast muscle quality of Plymouth Rock Chickens. Theresults of the test as followed:1Antimicrobial peptide agent significantly improve the production performanceof Plymouth Rock Chickens. Comparing with control group, total weight of ABP andABPY groups were improved by6.00%and11.67%respectively; daily weight gain ofABP and ABPY groups were improved by6.10%and11.89%significantly (P<0.01);feed conversion ratio were reduced by9.97%and16.01significantly (P<0.01); andthe survivability were improved by0.68%and1.36%insignificantly (P>0.05).2The dressed percentage and percentage of half-eviscerated yield of ABP Groupincreased by1.56%and2.88%compared with control group (P>0.05), and those ofABPY Group increased by2.80%and5.45%(P<0.01). Percentage of evisceratedyield, percentage of breast muscle and percentage of leg muscle showed someincrement insignificantly (P>0.05). Abdominal fat percentage of ABP and ABPY groups were reduced by19.40%and29.85%(P<0.01) and intermuscular fat width ofABP and ABPY groups I were reduced by4.37%and13.97%(P>0.05). Skin fatwidth of ABP Group increased by12.13%as compared with control group and skinfat width of ABPY Group decreased by3.89%insignificantly (P>0.05).3Flesh colour of ABP Group was lower than control group by1.90%(P>0.05)and flesh colour of ABPY Group was higher than that of control group by0.63%(P>0.05). Drip loss of ABP and ABPY groups were reduced by47.83%comparedwith control group (P>0.05). Muscle fiber diameter of ABP and ABPY groups werereduced by24.09%and27.48(P<0.01), and density of muscle fiber of ABP andABPY groups increased by54.55%(P<0.05) and76.70%(P<0.01) respectively.4Moisture and ash content of ABP and ABPY groups were higher than those ofcontrol group respectively by0.84%,1.19%, and4.67%and3.81%(P>0.05). Crudeprotein and crude fat of ABP and ABPY groups were lower than those of controlgroup respectively by3.18%and2.38%, and12.72%and8.58%(P>0.05).5Serine, tyrosine and arginine content of ABP and ABPY groups decreased by8.75%(P<0.05) and12.50%(P<0.01),14.01%and16.67%(P<0.01),10.07%and10.07%(P<0.01) compared with those of control group. Alanine and proline contentof ABP and ABPY groups increased by3.81%(P>0.05) and5.71%(P<0.05), and4.04%(P<0.05) and2.02%(P>0.05) compared with those of control group.6Calcium content of breast muscle of chickens in ABP Group increased by7.56%(P>0.05) and that of ABPY Group decreased by17.78%(P>0.05). P, Cr andCu content of ABP and ABPY groups decreased by respectively by7.98%and3.28%,3.03%and3.03%,17.07and12.20%(P>0.05). Zn and Fe content of ABP Groupdecreased by10.83%and7.74%(P>0.05), and those of ABPY Group increased by22.35%and23.06%(P>0.05). Se content of both ABP and ABPY groups increased by60%(P<0.01). Mn content of ABPY Group increased by23.53%(P<0.05). Mgcontent of ABP and ABPY groups increased respectively by6.67%and1.49%insignificantly (P>0.05).7Expression of H-FABP mRNA in breast muscle of chickens in ABP Group washigher than that of control group by42%(P>0.05), and was abundantly expressed inbreast muscle of chickens in ABPY Group, higher than that of control group by 48.59%yet insignificantly (P>0.05).Conclusion: Antimicrobial peptide agent supplementation in Plymouth RockChickens diets efficiently contributes to body weight evaluation and survivabilitywhereas reduced feed conversion ratio. Abdominal fat percentage was significantlyreduced, and the dressed percentage and percentage of half-eviscerated yield weresignificantly improved by antimicrobial peptide agents. As for the physicochemicalproperty, drip loss showed a declining trend while moisture and ash content of breastmuscle were on the rise with the use of antimicrobial peptide agents. The increasedmuscle fiber density and corresponding decreased muscle fiber diameter werebelieved to improve the meat quality and flavor of chicken. Crude protein and crudefat were slightly reduced, and free amino acids and essential amino acids were notimpacted. Microelements contents in breast muscle such as Se and Mn weresignificantly enhanced. On the mechanism part, H-FABP mRNA expression in breastmuscle of chicks with antimicrobial peptide agent supplementation increased yetinsignificantly. To conclude, ABPY enhanced performance of Plymouth RockChickens on production traits, dressed percentage, breast muscle meat quality andnutrient components. And the effects were better than those of mere antimicrobialpeptide (ABP). |
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