Molecular cloning and ontogenesis expression of fatty acid transport protein-1 in yellow-feathered broilers

Fatty acid transport protein-1 （FATP-1） is one of the important transporter proteins involved in fatty acid transmembrane transport and fat deposition. To study the relationship between FATP-1 mRNA expression and fat deposition, chicken （Gallus gallus） FATP-1 sequence was first cloned by rapid amplification of cDNA ends （RACE）. Tissue samples of chest muscle, leg muscle, subcutaneous fat, and abdominal fat were collected from six male and six female broilers each, at 22 days, 29 days, and 42 days, respectively. The tissue specificity and ontogenesis expression pattern of the FATP-1 mRNA of yellow-feathered broilers was studied by real-time reverse transcription polymerase chain reaction （RT-PCR）, and the fat deposition laws in different tissues were also compared. A 2,488 bp cDNA sequence of chicken FATP-1 was cloned by RACE （GenBank accession no. DQ352834）, including 547 bp 3＇ end untranslated region （URT） and 1,941 bp open reading frame （ORF）. Chicken FATP-1 encoded 646 amino acid residues, which shared 83.9% and 83.0% identity with those of human and rat, respectively. The results of quantitative PCR demonstrated a constant FATP-1 mRNA expression level in the chest muscle and subcutaneous fat of both male and female broilers at three stages, whereas the expression level of the FATP-1 mRNA in the leg muscle at 42 days was significantly higher than that at 22 days or 29 days. In the abdominal fat of male broilers, the gene expression significantly increased with age, whereas the female broilers showed a dramatic downregulation of FATP-1 expression in abdominal fat at 42 days. This suggested a typical tissue-and gender-specific expression pattern of chicken FATP-1, mediating the specific process of fatty acid transport or utilization in muscle and adipose tissues.

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.

Age and Gender Dependent Nutrient Composition of Feather and Feather-Free Body Fractions in Meat-Type Chickens

The objective of this research was to update current results about the nutrient composition of broiler chickens during the growth period up to market age. Two growth experiments were conducted for assessing the nutrient content of feathers and feather-free body of meat-type chickens (Ross 308). Both male and female birds were reared under uniform management conditions (floor pens;15 pens per gender;5 birds per pen). Experimental diets both for the starter (day 1 to 22) and the grower period (day 22 to 36) were based on corn, wheat, soybean meal, soybean protein concentrate and well balanced with feed amino acids. The feed protein quality was adapted to the ideal amino acid ratio and equated within both of the feeding periods by adjusting a constant mixture of the feed proteins. Each 15 birds per gender (3 pens of 5 birds) were selected and subsequently fasted for 24 h before quantitative de-feathering both at start of the experiment and further on weekly up to the end of the 5th week. Nutrient content was determined in representative samples of the feather and feather-free body fraction. In the feather dry matter (DM) very high crude protein (CP) concentrations (>96%) with low age-dependent and insignificant gender-specific differences were observed. In spite, a relatively high variation of CP content in the DM of feather-free body was found. Depending on age, the body CP significantly decreased with increasing age, but male birds yielded higher (p < 0.001) CP content. The crude lipid content of the feather-free and whole empty body significantly increased with age and was higher in female as compared to male birds (p < 0.001). Depending on age and gender, the crude ash content both in feathers and feather-free body of modern fast-growing chickens was rather low and with very low variation.

Age and Gender Dependent Amino Acid Concentrations in the Feather, Feather-Free and Whole Empty Body Protein of Fast Growing Meat-Type Chickens

Two consecutive growth experiments with meat-type chickens (Ross 308) were conducted in order to quantify the age-dependent amino acid (AA) content in the whole body protein of male and female birds based on experimental data of the feather and feather-free body protein fractions. Birds were reared under uniform housing and feeding conditions (floor pens, 15 pens per gender, 5 birds per pen) during the starter (day 1 to 22) and grower period (day 22 to 36). Both the starter and grower diet based on corn, wheat, soybean meal, soybean protein concentrate and feed amino acids was formulated to ensure an equal feed protein quality close to the ideal amino acid ratio by adjusting a constant mixture of the feed proteins. At start of the experiment and further on weekly up to the end of the 5th week, 15 birds per gender (each 3 pens of 5 birds) were selected and fasted for 24 h, to emptying of gastro-intestinal tract, respectively. Subsequently, birds were euthanized and the feathers were manually removed. Nitrogen (N) and AA content were determined both in the feather and feather-free body fraction. The concentration of individual AAs in both of body protein fraction is varying considerably. Explicitly higher Cys, Ser and Pro but importantly lower Met, Lys and His concentrations were found in the feather protein. Furthermore, significant differences (p for nearly all AAs of the studied body protein fractions and the whole empty body protein dependent on age of birds were observed. Especially high deviations were obtained during the first week of age and at the end of the experiment. According to this observed variation of AA concentrations must be concluded that the body AA composition of meat-type chickens during growth is not constant. The detected gender-specific differences for several AAs in the feather and body protein of male and female birds were rather low and with very low variation.

Effects of Different Dietary Energy and Protein Levels on Meat Performance and Meat Quality of Jinghai Yellow Chickens

To investigate the effect of different dietary energy and protein levels on meat performance and meat quality of Jinghai yellow chickens, 480 43-day old Jinghai yellow chickens with similar weight were randomly divided into four experimental groups： experimental group 1 （protein 15%, metabolic energy 9.95 MJ/kg）, experimental group 2 （protein 16%, metabolic energy 10.95 MJ/kg）, experimental group 3 （protein 17%, metabolic energy 12.65 MJ/kg） and experimental group 4 （ protein 18%, metabolic energy 13.95 MJ/kg）, respectively. All chickens were slaughtered at 112-day old. The breast and leg muscles of Jinghai yellow chickens were collected, to determine the slaughter performance, conventional meat quality and muscle chemical indicators. The results indicated that dressing-out percentage and eviscerated yield percentage in four experimental groups were above 87.27% and 67.00%, respectively; other slaughter performance indicators exhibited no significant differences among various groups （P 〉 0.05 ） ; breast muscle color of hens in experimental group 4 varied significantly from that in other three groups （ P 〈 0.05 ） ; leg muscle color of hens in experimental group 2 varied extremely significantly from that in other three groups （ P 〈 0.01 ） ; water-holding capacity of breast muscles of hens in experimental group 3 was significantly higher than that in experimental group 4 （P 〈 0.05 ） ; thiamine content of breast muscles of cocks in experimental group 3 was significandy higher than that in experimental group 2 （ P 〈 0.05 ） ; however, other properties exhibited no significant differenees among various groups （P 〉 0.05 ）.

Selection Progress of Wannan Native Chicken's Fast and Slow Feathering Lines

[Objective]This experiment aimed to establish fast and slow feathering lines from purified and rejuvenated core breeding flock. [Method] Individual and family selection were used for continuous selection from zero to the second generation. [Result]The results showed that in the fast feathering line,the average weight gain was improved by 108. 34 g per generation in roosters at the age of 20 weeks while a 54. 5 g increase was got per generation in hens. Hen housed egg production was increased from 150 to 170 at the age of 66 weeks,and the healthy rate of chicken flock was raised by 0. 7 percent. In the slow feathering line,the average weight gain was increased by 156. 6g per generation in roosters while a 38. 9 g increase was got per generation in hens,and the hen housed egg production was increased from 158 to 179 at the age of 66 weeks. [Conclusion] This research had a great significance in increasing native chicken＇s production performance and developing its market competitiveness.

Age and Gender Depending Growth of Feathers and Feather-Free Body in Modern Fast Growing Meat-Type Chickens

Two growth experiments with fast growing meat type chickens (Ross 308) were conducted to assess the growth of feathers and feather-free body dependent on age and gender (male:female ratio = 1:1). Birds were reared under uniform management and feeding conditions (floor pens;15 pens per gender;5 birds per pen) during the starter (day 1 to 22) and grower period (day 22 to 36). Diets were based on corn, wheat, soybean meal, soybean protein concentrate and balanced with feed amino acids to ensure an equal feed protein quality close to the ideal amino acid ratio by a constant mixture of the feed proteins. At start of the experiment and further on weekly up to the end of the 5th week, 15 birds per gender (each 3 pens of 5 birds) were selected and 24 h fasted before quantitative de-feathering. Both feather and feather free body fractions were significantly increased with increasing age of the birds (p < 0.001). Feather percentage as related to the empty body weight increased non-linearly from approximately 2% at the end of the first week to about 4% at the end of the experiment. Feather percentage and dry matter content of the feather-free body was significantly higher in female birds (p < 0.001) as compared to males. Further investigations will show how this varying proportions impact on nutrient deposition of modern meat-type chickens dependent on age and gender, respectively.

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 Diet with Picria fel-tarrae Lour Particle on the Growth Performance, Blood Biochemical Indexes, Immune and Antioxidant Function of Hongguang Yellow Chickens

[Objectives]To investigate the effect of diet with Picria fel-tarrae Lour particle(PFLp)on growth performance,blood biochemical indexes,immune and antioxidant function of Hongguang yellow chickens(HYC).[Methods]80 HYC in age of 1 d were divided into 4 groups randomly and each group was assigned to 5 replicates with 24 chicks in each replicate.Group A was control group fed only basal diet.Group B,C and D were treatment groups and fed diets with 0.125%,0.25%and 0.50%of PFLp respectively during the trial of 49 d.Serum samples were taken from 10 chicks in each group in the age of 21,35 and 49 d respectively and analyzed for biochemical,immune and antioxidant parameters in blood.[Results]ADG from group C in 21 d was increased significantly than that from group A,B and D(P<0.01),and ADG in 35 d from group C was also significantly greater than that from group A,B and D(P<0.05),but not much difference was found on ADG among the 4 groups in 49 d(P>0.05);ADFI from group C in 35 d was significantly higher than that from group A,B and D(P<0.05).ADFI from group C in 21 and 49 d were also higher than that from group A(P>0.05).FCR from group C in 21 d was much better than that from the other three groups(P<0.01).Death rate of group C was 50 percent lower than group A;There was no difference occurred in serum biochemical and immune parameters among the 4 groups during the trial(P>0.05).However,the T-AOC from group C and D in 21 d was enhanced significantly than that from group A and B(P<0.01),and the one from group C in 35 d was also increased greatly than that from group A,B and D(P<0.05).GSH from group C and D in 21 d was much higher than that from group A and B(P<0.05),and the ones from group C and D in 35 d were also significantly higher than those from group A and B(P<0.01).T-SOD in three stages trended up also in group C and D(P>0.05).[Conclusions]The diet with 0.25%PFLp in 21 and 35 d could dramatically improve the growth performance,significantly increase the antioxidant capacity and effectively reduce death rate.Diet with 0.25%PFLp is the most appropriate among the three different additions.

Relationship between White-partridge Feather Trait and SLC45A2 Polymorphism in Wenchang Chicken

[Objective]The paper was to study the inheritance of white-partridge feather trait in Wenchang chicken and identify the related genetic variation,so as to provide references for the utilization of white-partridge population of Wenchang chicken and molecular marker-assisted selection of white-partridge feather trait.[Method]The inheritance of white-partridge feather trait was studied by reciprocal cross test.SLC45A2 was selected as a candidate gene based on the genetic characteristics of white-partridge feather and results of previous researches.The variation in the exon domain of SLC45A2 gene was analyzed by re-sequencing method.The relationship between missense mutation/nonsense mutation in the exon domain and white-partridge feather trait was verified.[Result]Reciprocal cross test showed that white-partridge feather trait was associated recessive inheritance compared with yellow-partridge feather.The amplification results indicated that there were five SNPs in SLC45A2 gene,in which three were located in exon domain,including two missense mutations(c.a74g and c.gll54c)and one synonymous mutation(c.c561t).The missense mutation was verified with Wenchang chicken Bawang chicken,Qingyuan partridge chicken,Xinghua chicken and red jungle fowl as materials.The results demonstrated that c.g1154c locus of SLC45A2 gene was completely linked with white-partridge feather trait.[Conclusion]The trait of white-partridge feathers showed recessive inheritance and c.g1154c locus might be the causation.

Chicken Feathers Waste Management by Microbial as a Sustainable and Tool Environmental Friendly

Valorizing chicken feather agro-wastes nowadays is imperative, if these wastes are disposed of without treatment, they could contribute to environmental problems. Conventional methods of processing chicken feathers such as landfilling, chemical treatment and burning are costly, non-time consumable and are toxic to the environment. Microbial hydrolysis, on the contrary, is now considered the main environmental-friendly recycling alternative. Hence, the aim of this study is to isolate keratinolytic bacteria with efficient feather hydrolysis, to optimize some of the physical parameters that could affect both bacterial growth and consequently its degrading ability. Results demonstrated an efficient feather degrading ability of newly identified Bacillus sp. D4 strain isolated from chicken feathers under optimal mesophilic temperature 37°C, pH 8.0 and 106 CFU/mL cell size inoculum, interpreted by highest keratin activity (55.0 ± 1.35 U/mL) and (54.3 ± 1.5 U/mL) respectively and higher total protein content in the cell free supernatant of 0.65 mg/mL. Beyond these parameters values, a moderate enzyme activity was observed at 40°C (35.1 ± 2 U/mL), 25°C (30.1 ± 2 U/mL), similarly at the initial pH 7.5 (52.3 ± 2 U/mL), pH 9.0 (49.0 ± 1.2 U/mL) and pH 10.0 (38.2 ± 1.35 U/mL). Bacillus sp. D4, on the other hand, was not able to tolerate high alkaline pH value 11.0 nor acidic pH 4.0 and 5.0 and high temperature of 55°C, correspondingly low enzyme activity was noted (19.0 ± 1 U/mL).

基于转录组测序研究调控黄羽肉鸡干毛性状关键基因和信号通路

【目的】通过比较干毛和未干毛羽毛毛囊的形态学和基因表达差异,挖掘调控黄羽肉鸡羽毛干毛性状的重要候选基因和信号通路。【方法】分别采集背部未干毛和干毛羽毛皮肤组织样本各3个,运用组织切片技术,比较干毛和未干毛羽毛毛囊形态学差异;运用RNA-seq技术,比较两组样本之间的差异表达基因(differentially expressed genes,DEGs),并对其进行功能富集分析和蛋白互作网络构建;采用荧光定量PCR技术(RT-qPCR)对测序结果准确性进行验证。【结果】证实未干毛羽毛的毛囊处于生长期,已干毛的羽毛毛囊处于静止期。以未干毛毛囊(生长期)皮肤样本为对照,在干毛毛囊(静止期)皮肤样本中发现了942个DEGs(|fold-change|>2和P<0.05),其中384个基因表达下调,558个基因表达上调。Go功能分析显示细胞分裂、周期调控等相关生物过程被显著富集(P<0.05)。KEGG分析发现,MAPK、TGF-β、p53及DNA复制等相关信号通路被显著富集(P<0.05)。构建差异蛋白相互作用(PPI)网络,通过CytoHubba分析获得6个hub基因,分别为CDK1、MAD2L1、BUB1、CCNB2、PLK1和BUB1B。GSEA富集分析筛选到紧密连接、胰岛素、MAPK、TGF-β和细胞周期等信号通路与鸡羽毛毛囊生长周期显著关联(|NES|>1,FDR<0.25)。RT-qPCR结果显示8个DEGs表达趋势与RNA-seq结果基本一致。【结论】鸡羽毛的干毛性状与毛囊周期发育相关,MAPK和TGF-β等信号通路可能通过调控细胞周期相关基因的表达在羽毛生长发育中发挥重要作用;结果为进一步深入了解黄羽肉鸡羽毛干毛性状分子调控机制提供了基础资料。

低蛋白日粮对黄羽肉鸡生长性能及胴体品质的影响

试验旨在研究低蛋白日粮对黄羽肉鸡生长性能、胴体品质及肉质的影响。试验选取1日龄慢速型母鸡360羽,设对照组、试验组,每组6个重复,每个重复30只鸡。试验组1~6周(w)、7~13 w、14~19 w阶段日粮粗蛋白浓度,分别设定为对照组的90%、95%、100%,配方中增加玉米副产物比例、降低豆粕与大豆油用量。结果显示,相比于对照组,试验组鸡各阶段体重明显下降(P<0.05),1~6 w增重明显降低(P<0.01)、料重比增高(P<0.01),全程料重比无显著变化(P>0.05);鸡腹脂率显著下降(P<0.05),胸肌a值、肉色L值优于对照组(P<0.05);单位增重所需日粮粗蛋白下降1.7%,饲料成本下降7.1%。综上所述,在本研究条件下,下调生长前、中期日粮的粗蛋白浓度会明显降低黄羽肉鸡全期生长速度,但能节约增重饲料成本,对胴体品质、肉质有一定的改善作用。

笼养密度对公母分饲黄羽肉鸡生长性能、免疫器官发育、抗氧化能力、肠道组织形态及免疫相关基因mRNA表达的影响

本试验旨在探讨笼养密度对公母分饲黄羽肉鸡生长性能、免疫器官发育、抗氧化能力、肠道组织形态及免疫相关基因mRNA表达的影响。选用21日龄黄脚麻鸡720只,3层层叠式笼内饲喂,鸡笼规格为长×宽×高=1.2 m×0.8 m×0.4 m,公鸡和母鸡分开饲养,均随机分为4组(每组5个重复),笼养密度分别为15(低密度组)、17(中密度组)、19(中高密度组)和21只/m 2(高密度组)。试验期42 d。结果表明:1)对于公鸡,21~42日龄时,高密度组平均日采食量显著低于低密度组和中密度组(P<0.05);43~63日龄时,中高密度组和高密度组平均日采食量显著低于低密度组和中密度组(P<0.05),中高密度组和高密度组平均日增重显著低于低密度组(P<0.05)。对于母鸡,21~42日龄时,中高密度组和高密度组平均日采食量显著低于低密度组(P<0.05),高密度组平均日增重显著低于低密度组(P<0.05);43~63日龄时,高密度组平均日采食量显著低于低密度组和中密度组(P<0.05),中高密度组平均日增重显著低于低密度组(P<0.05)。2)对于公鸡,低密度组肝脏重量显著低于其他各组(P<0.05),肝脏指数显著低于高密度组(P<0.05)。3)对于母鸡,中密度组血清超氧化物歧化酶活性显著高于高密度组(P<0.05),中高密度组血清丙二醛含量显著高于高密度组(P<0.05)。4)对于公鸡,中密度组空肠绒毛高度/隐窝深度显著高于高密度组(P<0.05)。对于母鸡,高密度组十二指肠隐窝深度显著高于中高密度组(P<0.05),中高密度组十二指肠绒毛高度/隐窝深度显著高于高密度组(P<0.05);高密度组空肠绒毛高度显著低于中密度组和中高密度组(P<0.05),高密度组空肠绒毛高度/隐窝深度显著低于低密度组(P<0.05);高密度组回肠隐窝深度显著高于其他各组(P<0.05)。5)对于公鸡,中高密度组空肠肿瘤坏死因子-α(TNF-α)mRNA相对表达量显著高于其他各组(P<0.05)。对于母鸡,中高密度组空肠核因子E2相关因子2(Nrf2)和Toll样受体4(TLR4)mRNA相对表达量显著高于低密度组(P<0.05)。由此可见,高笼养密度会对黄羽肉鸡生长性能、抗氧化能力、肠道组织形态等相关指标产生影响;笼养密度可能通过影响肠道抗氧化和免疫相关基因表达影响黄羽肉鸡肠道免疫功能。

大豆活性肽对黄羽肉鸡生长性能、屠宰性能、肉品质、免疫功能及抗氧化能力的影响

本文旨在研究大豆活性肽对黄羽肉鸡生长性能、屠宰性能、肉品质、免疫功能及抗氧化能力的影响。选用1日龄健康大恒黄羽肉鸡公鸡800只,随机分成5组,每组10个重复,每个重复16只鸡。对照组饲喂基础饲粮,抗生素组饲喂基础饲粮+0.2 g/kg恩拉霉素,试验组分别饲喂以0.2%、0.4%、0.6%的大豆活性肽替代基础饲粮中豆粕的试验饲粮。试验期70 d。结果表明:1)抗生素组和0.2%大豆活性肽组的末重、平均日增重显著高于对照组(P<0.05),料重比显著低于对照组(P<0.05)。各组之间平均日采食量无显著差异(P>0.05)。2)各组之间屠宰率、全净膛率、半净膛率、胸肌率、腿肌率和腹脂率无显著差异(P>0.05)。3)各组之间血常规指标无显著差异(P>0.05)。4)0.2%大豆活性肽组的胸肌45 min肉色显著高于对照组、抗生素组和0.4%大豆活性肽组(P<0.05)。各组之间胸肌45 min和24 h pH、24 h肉色、滴水损失、蒸煮损失以及肌纤维直径、横截面积和密度无显著差异(P>0.05)。5)抗生素组和0.2%、0.4%、0.6%大豆活性肽组的血清溶菌酶含量显著高于对照组(P<0.05)。0.2%大豆活性肽组的血清白细胞介素-1β(IL-1β)和干扰素-γ(IFN-γ)含量显著低于对照组(P<0.05),血清白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、免疫球蛋白G(IgG)、免疫球蛋白A(IgA)和免疫球蛋白M(IgM)含量显著高于对照组(P<0.05)。6)各组之间脾脏指数和法氏囊指数无显著差异(P>0.05)。7)抗生素组和0.2%大豆活性肽组的血清总抗氧化能力(T-AOC)显著高于对照组(P<0.05)。各组之间血清谷胱甘肽过氧化物酶(GSH-Px)和总超氧化物歧化酶(T-SOD)活性无显著差异(P>0.05)。由此可见,饲粮中添加0.2%大豆活性肽可提高黄羽肉鸡生长性能和免疫功能,改善肉品质和增强机体抗氧化能力,且具有替代抗生素的作用。

隐性白羽鸡新品系选育及其配套利用

采用个体选择与家系选择方法,以生长性能和产蛋性状为主选指标,对隐性白羽鸡基础群进行选育,建立了隐性白羽鸡新品系,再利用隐性白羽鸡新品系作为母本进行二系配套,并测定其性能。结果表明,通过4个世代的选育,隐性白羽鸡新品系初生重降低2.9 g,公鸡15周龄体重降低486.0 g,43周龄体重降低562.9 g;母鸡15周龄体重降低334.6 g,43周龄体重降低404.5 g,开产日龄提前了5.2 d,43周产蛋数提高6.7个。以隐性白羽鸡新品系作为母本的二系配套J×W组的屠宰性能和体尺指标均优于Y×W组。隐性白羽鸡新品系经过4个世代的选育,产蛋性能和体重均得到较大改善,杂交配套效果良好。

基于相关性分析和主成分分析的宁都黄鸡肉品质评价研究

目的探讨不同日龄宁都黄鸡肉品质评价的合理模型。方法选择同一批次的宁都黄鸡进行饲养,分别在84、120和200日龄进行屠宰,取胸肌进行肉品质检测并进行相关性分析和主成分分析,构建不同日龄的肉品质评价模型。结果主成分分析提取出4个主成分因子,第一主成分的方差贡献率为23.98%,第二主成分为18.47%,第三主成分为16.69%,第四主成分为11.47%,累积方差贡献率为70.62%,且特征值均大于1。建立了宁都黄鸡不同日龄肉品质综合评价模型为F=0.24F_(1)+0.18F_(2)+0.17F_(3)+0.12F_(4),200日龄宁都黄鸡评分最高。结论基于主成分分析综合评价模型对不同日龄宁都黄鸡肉品质进行分析是可行和客观的。

基于改进ConvNeXt模型的黄羽鸡表皮层黑色素智能分级方法

为解决活体黄羽鸡表皮层黑色素分级方法成本高、效率低下、分级环境易受环境光干扰等问题,该研究探索一种基于ConvNeXt模型的黄羽鸡表皮层黑色素智能分级方法ConvNeXt-WPCA,用于实现活体黄羽鸡表皮层黑色素智能分级。ConvNeXt-WPCA模型通过以下3点改进提高模型对黄羽鸡黑色素的识别效果:1)针对黄羽鸡黑色素图像RGB三通道内黑色素信息分布不均衡问题,改变输入图片通道权重来增强模型对黑色素特征的提取能力;2)使用部分卷积代替深度可分离卷积,减少模型计算量和内存访问次数提高对计算资源的利用率;3)引入坐标注意力机制,引导模型关注黄羽鸡胸腹部及肛门附近皮肤提升模型精度。同时,该研究还设计一种双光源图像获取装置,分别在自然光和偏振光条件下拍摄黄羽鸡样本,以减小分级结果受环境光干扰的影响,并探索偏振光在黑色素分级任务中的应用潜力。结果表明ConvNeXt-WPCA模型相较标准ConvNeXt模型,针对自然光下黄羽鸡黑色素图像数据集分级准确率提升9.68个百分点,最终达到89.03%的识别准确率,针对偏振光下黄羽鸡黑色素图像数据集分级准确率提升15.26个百分点,最终达到98.87%的识别准确率。该研究证实基于偏振光条件获取的黄羽鸡表皮层黑色素图像分级效果优于自然光条件,提出的ConvNeXt-WPCA黄羽鸡表皮层黑色素分级方法识别准确率高,同时模型参数量及浮点计算量均有降低,为黄羽鸡表皮层黑色素智能分级实际应用提供了理论基础及技术支持。

不同材料复合添加对土壤铬形态的影响

以铬污染黄壤为研究对象,选择有机材料(泥炭)、pH值调节剂(沸石)、生物炭(鸡粪)3种不同种类的土壤重金属污染改良剂,采用正交试验L_(9)(3^(4))设计和室内盆栽试验,考察不同复合材料组对土壤中重金属铬形态、pH值、有机质含量的影响。结果表明:沸石的添加提高了土壤pH值、有机质含量,增加了土壤可还原态、可氧化态铬含量;鸡粪的添加通过提高土壤pH值从而增加土壤可还原态铬的含量;泥炭的添加提高了土壤有机质含量、土壤可氧化态铬含量,降低了土壤可交换态铬含量。