Nonphytate Phosphorus Requirement and Efficacy of a Genetically Engineered Yeast Phytase for Yellow Broilers at 22- to 42-d-Old Age

An experiment was conducted to investigate the requirement of nonphytate phosphorus（nPP） and efficacy of a genetically engineered yeast phytase（PHY A） for Lingnan yellow broilers from 22-to 42-d-old age.A total of 1 320 1-d-old male chicks were randomly divided into 11 dietary treatment groups,which consisted of 4 replicate floor pens with 30 birds per pen.The control group（treatment 1） was fed with basal diet of nPP 0.08% without dicalcium phosphate or phytase supplementation.Dietary levels of nPP were 0.16,0.24,0.32,0.40,0.48,and 0.56%,respectively,for treatments 2 to 7,through addition of dicalcium phosphate（chemistry grade） to the basal diet.Diets of treatments 8 to 11 were supplemented with PHY A at 200,400 and 600 U kg-1,a commercial phytase product（PHY B） at 400 U kg-1 level,respectively.The birds in 0.32-0.56% nPP groups gained more than those of the other groups（P0.05）.The nPP supplementation significantly improved feed intake（P0.05）.The feed gain ratio was significantly decreased by 0.40% nPP diet compared to the control birds（P0.05）.The level of 0.48% nPP was required for optimum tibia development.The additions of PHY A at 400 and 600 U kg-1 level and PHY B all significantly improved ADG（P0.05）,ADFI（P0.05）,and dry defatted tibia weight（P0.05）.Similarly,the percentage of tibia ash was increased by 600 U kg-1 PHY A supplementation（P0.05）.The requirement of nPP for maximal ADG and highest percentage tibia ash both was 0.40%.The phosphorus equivalency value of PHY A was estimated as 685 U kg-1 for male yellow broilers of 22-to 42-d-old age.

Effects of Dietary Isoflavone Supplementation on Meat Quality and Oxidative Stability During Storage in Lingnan Yellow Broilers

To investigate the effects of a synthetic isoflavone （SI） on meat quality and oxidative stability, 1 500 43-d-old Lingnan yellow male broilers were randomly assigned to five dietary treatments： diets supplemented with 0, 10, 20, 40, or 80 mg SI kg-1, fed ad libitum for a period of 3 wk. After refrigerated storage, a＊ value of the meat increased with dietary SI supplementation using 10 and 40 mg kg-1 level （P〈0.05）, L＊ value decreased （P〈0.05）, and 40 mg kg-j increased the pH （P〈0.05）. Supplementation with SI, at all levels, increased water holding capacity （P〈0.05） and decreased lactic acid content of meat （P〈0.05）. The concentration of malondialdehyde at 72 h decreased linearly （P=0.005） and quadratically （P=0.004） with increasing levels of SI. Dietary SI at 20 and 40 mg kg-1 levels enhanced total superoxide dismutase activity in meat （P〈0.05）. Meat pH quadratically decreased as the storage time increased （P〈0.05）, with the highest value at 24 h （P〈0.05）. Lactic acid and malondialdehyde concentrations of meat increased over time, with value at 96 h being far higher than at earlier times （P〈0.05）. Supplemental SI linearly and quadratically increased the mRNA abundance ofglutathione peroxidase （GPX） （P=0.001 and P=0.002） and catalase （CAT） （P=0.003 and P=0.006） in breast muscle. The results from this study indicate that dietary supplementation with SI can improve meat quality during refrigerated storage by decreasing lipid peroxidation and enhancing oxidative stability and, for male broilers from 43 to 63 d of age, the optimal level of SI was 40 mg kg-1.

Effects of rearing system(floor vs.cage)and sex on performance,meat quality and enteric microorganism of yellow feather broilers

This study investigated the effects of floor and cage rearing systems on performance,meat quality,and enteric microorganisms of male and female yellow feather broilers.Two hundred Xueshan chickens(42 days old;100 of each sex)were divided into four groups,according to sex and rearing system(stainless-steel cage or litter floor).Male and cage-reared broilers exhibited better(P<0.001)performance and higher(P≤0.001)eviscerated percentage than female and floor-reared broilers.The interaction between rearing system and sex had an effect(P<0.05)on the percentage of breast and thigh muscles.Female floor-reared broilers presented the highest(P<0.02)percentage of breast and thigh muscles among all the groups.In both sexes,the abdominal fat content in cage-reared broilers was higher(P<0.01)than that in floor-reared broilers.Female cage-reared broilers exhibited better(P<0.05)meat quality of breast muscle than other groups.An analysis of welfare observations indicated that the feather quality of floor-reared broilers was better(P<0.01)than that of cage-reared broilers,whereas the gait scores were not significantly affected(P>0.05)by rearing system.The enteric microbiota assessment by 16 S rRNA amplicon-based sequencing showed that Firmicutes,Proteobacteria,and Bacteroidetes were the most prevalent phyla in both rearing systems,and that the cecum was relatively stable in terms of microbiome composition.Floor-reared broilers exhibited a richer diversity of bacteria in the intestinal tract than cage-reared broilers,while alpha diversity was not significantly different(P>0.05)among the groups.The ratio of Bacteroidetes to Firmicutes and the abundance of Helicobacter and Romboutsia could potentially affect the production of broilers.These findings indicate that cage rearing improved the production of male Xueshan broilers,which may be due to the difference in enteric microbiota between cage and floor rearing systems.

Effects of Small Peptide Chelated Copper,Iron,Manganese and Zinc on Growth Performance,Chicken Quality and Antioxidant Capacity of Yellow Feather Broilers

[Objective]The paper was to study effects of small peptide chelated trace elements(copper,iron,zinc and manganese)on growth performance,chicken quality and antioxidant capacity of rapid yellow feather broilers.[Method]Three hundred one-day-old yellow feather broilers with similar body weight were selected and randomly divided into three treatments:inorganic trace element group(basal diet+inorganic trace elements),organic trace element group(basal diet+small peptide chelated trace elements)and compound group(basal diet+50%inorganic trace elements+50%small peptide chelated trace elements).There were 10 replicates per treatment and 10 chickens per replicate.The trial lasted for 63 d.[Result]①Compared to inorganic trace element group,average daily gain(ADG)of yellow feather broilers in organic trace element group was significantly increased over the whole period(P<0.05).②There was no significant difference in slaughter performance and immune organ indices among the three test groups(P>0.05).③There was no significant difference in breast muscle pH,chicken color,drip loss,and shear force among the three groups(P>0.05),but cooking loss of chicken breast in inorganic trace element group was 27.46%and 22.53%higher than those in organic trace element group and compound group,respectively(P<0.05).④MDA content in serum in organic trace element group was 15.61%lower than that in inorganic trace element group(P<0.05).[Conclusion]Complete substitution of inorganic copper,iron,zinc and manganese by small peptide chelated copper,iron,zinc,and manganese significantly increases ADG of broilers,improves quality of chicken breast,and enhances antioxidant capacity.

Novel multiple object tracking method for yellow feather broilers in a flat breeding chamber based on improved YOLOv3 and deep SORT

Aiming at the difficulties of the health status recognition of yellow feather broilers in large-scale broiler farms and the low recognition rate of current models,a novel method based on machine vision to achieve precise tracking of multiple broilers was proposed in this paper.Broilers’behavior in the breeding environment can be tracked to analyze their behaviors and health status further.An improved YOLOv3(You Only Look Once v3)algorithm was used as the detector of the Deep SORT(Simple Online and Realtime Tracking)algorithm to realize the multiple object tracking of yellow feather broilers in the flat breeding chamber,which replaced the backbone of YOLOv3 with MobileNetV2 to improve the inference speed of the detection module.The DRSN(Deep Residual Shrinkage Network)was integrated with MobileNetV2 to enhance the feature extraction capability of the network.Moreover,in view of the slight change in the individual size of the yellow feather broiler,the feature fusion network was also redesigned by combining it with the attention mechanism to enable the adaptive learning of the objects’multi-scale features.Compared with traditional YOLOv3,improved YOLOv3 achieves 93.2%mAP(mean Average Precision)and 29 fps(frames per second),representing high-precision real-time detection performance.Furthermore,while the MOTA(Multiple Object Tracking Accuracy)increases from 51%to 54%,the IDSW(Identity Switch)decreases by 62.2%compared with traditional YOLOv3-based objective detectors.The proposed algorithm can provide a technical reference for analyzing the behavioral perception and health status of broilers in the flat breeding environment.