Are dual-purpose and male layer chickens more resilient against a low-protein-low-soybean diet than slow-growing broilers?

RNA sequencing reveals lncRNA-mediated non-mendelian inheritance of feather growth change in chickens

Background

Long non-coding RNAs (lncRNAs) play an essential role in biological processes. However, the expression patterns of lncRNAs that regulate the non-Mendelian inheritance feather phenotypes remain unknown.

Objective

This study aimed to compare the expression profiles of lncRNAs in the follicles of the late-feathering cocks (LC) and late-feathering hens (LH) that followed genetic rules and the early-feathering hen (EH) and early-feathering cock (EC) that did not conform to the genetic laws.

Methods

We performed RNA sequencing and investigated the differentially expressed lncRNAs (DElncRNAs) between the early- and late-feathering chickens, which function by cis-acting or participate in the competing endogenous RNA (ceRNA) network.

Results

A total of 53 upregulated and 43 downregulated lncRNAs were identified in EC vs. LC, and 58 upregulated and 109 downregulated lncRNAs were identified in EH vs. LH. The target mRNAs regulated by lncRNAs in cis were enriched in the pentose phosphate pathway, TGF-β signaling pathway and Jak-STAT signaling pathway in EC vs. LC and were associated with the TGF-β signaling pathway, Wnt signaling pathway, p53 signaling pathway and Jak-STAT signaling pathway in EH vs. LH. In addition, the lncRNA-mediated ceRNA regulatory pathways of hair follicle formation were mainly enriched in the TGF-β signaling pathway, Wnt signaling pathway, melanogenesis, and calcium signaling pathways. The levels of ENSGALG00000047626 were significantly higher in the late-feathering chickens than in the early-feathering chickens, which regulated the expression of SSTR2 by gga-miR-1649-5p.

Conclusion

This study provides a novel molecular mechanism of lncRNA’s response to the feather rate that does not conform to the genetic laws in chickens.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13258-022-01304-2.

Dual-Purpose Poultry in Organic Egg Production and Effects on Egg Quality Parameters

Egg laying genotypes have been selected for generations due to their high yield and egg quality, resulting in efficient feed utilization and low body weight; hence, they are not suitable for meat production. This imposes an issue for the male layer chicks, which are killed at one day old. Because of ethical and food waste concerns, the search for suitable dual-purpose genotypes in order to avoid euthanasia of male day-old chicks has intensified. The aim of the present study is to evaluate potential dual-purpose genotypes for their egg quality compared to a representative egg laying genotype. Two dual-purpose genotypes with divergent characteristics were evaluated: genotype A represented an experimental crossbreed based on a broiler type male and an egg layer female, and genotype C was a crossbreed of a layer type. These were compared to a rustic genotype B and a control genotype D, which was an egg layer. Eggs were collected six times during the period of 21–54 weeks of hen age, i.e., a total of 990 shell eggs were analyzed. Examined parameters were weights of egg, shell, yolk, and albumen, by calculating their relative proportions. Shell quality was assessed by shell strength, shell stiffness, and shell thickness. Yolk quality was determined as yolk color and inclusions of blood and meat spots, and albumen quality was evaluated in terms of pH and dry matter (DM) content. The egg layer genotype produced the smallest eggs with least blood and meat spot inclusions compared to that produced by the three dual-purpose genotypes. Shell quality was superior for the layer genotype. However, the experimental genotype A laid eggs of comparable shell quality, albumen DM, and yolk weight, but also with the darkest and most red-yellow colored yolk. The two other dual-purpose genotypes produced eggs of low-medium quality. In conclusion, the genotype A could serve as dual-purpose genotype from an egg quality perspective.

Breast meat quality in males and females of fast-, medium- and slow-growing chickens fed diets of 2 protein levels

The aim of this study was to evaluate the effects of genotype, sex, dietary protein level, and their interactions on select carcass characteristics and meat quality of fast- (Ross 308), medium- (Hubbard JA757) and slow-growing (ISA Dual) chickens (n = 2,520). The diet of the low-protein group of chickens had 6% lower CP than the commercial diet fed to the control group. When the chickens reached an average live weight of 2 kg, 10 males and 10 females of each genotype and the diet were selected for slaughter and breast meat–quality analysis. The dressing out and breast percentages were lower in the JA757 (−2.0 and −5.9%, respectively) and ISA Dual chickens (−9.9 and −14.3%, respectively) than those in the Ross 308 chickens. The ISA Dual chickens had higher abdominal fat percentage, higher DM and protein contents and lower ether extract content and shear force value in breast meat than the other genotypes. Significant interaction effects of genotype, sex, and diet were found on the color of breast skin. Among the various combinations of genotype, sex, and diet group, Ross 308 females fed the low-protein diet had the highest redness and yellowness of breast skin, highest pH45 value, and largest fibers, whereas ISA Dual females had the lowest color parameters and pH45 value, and ISA Dual males had the smallest muscle fibers. The low-protein diet was associated with decreased abdominal fat percentage and changes in meat quality parameters, including increased darkness, meat color intensity, drip loss, and muscle fiber area, in all genotypes. The results indicated greater differences in meat quality owing to genotype than to sex or dietary protein level.

Research Note: The effects of genotype, sex, and feeding regime on performance, carcasses characteristic, and microbiota in chickens

The aim of the present study was to evaluate the effects of quantitative feed restriction (FR) in fast-, medium-, and slow-growing meat-type male and female chickens on their growth, feed consumption, economic efficiency, carcass composition, and gastrointestinal microbiota. In the experiment, fast-growing Ross 308, medium-growing Hubbard JA 757 and slow-growing ISA Dual chickens of both sexes were exposed to quantitative FR between 14 and 21 d of age. During the FR, restricted chickens received 70% of the amount of feed consumed by the ad libitum (AL) group. Live weight at the end of the experiment was affected by genotype (P < 0.001), sex (P < 0.001), feeding regime (P < 0.001), and their interaction (P < 0.001). The highest final weight was in AL and FR ISA Dual males and the lowest was in AL and FR females of the same genotype. A similar tendency was observed in daily weight gain and feed intake. Carcass traits were predominantly affected by genotype. However, interactions of genotype, sex, and feeding regime were observed in thigh (P < 0.001) and abdominal fat (P < 0.001) proportions. Concerning gastrointestinal microbiota, only Escherichia coli was affected by genotype. Feed restriction in slow-growing dual-purpose chickens might improve economic potential; however, further research is needed to reveal the involvement of variable processes, which are unclear and affect production.

Are Dual-Purpose Chickens Twice as Good? Measuring Performance and Animal Welfare throughout the Fattening Period

Chickens are the world's most widely used farm animal and have a significant genetic diversity. In the current study, we investigated three strains for their suitability as dual-purpose chickens, with a focus on the fattening ability and welfare of the cockerels: 1. layer cockerels (Lohmann Brown, LB, n = 714); 2. cockerels of a dual-purpose hybrid (Lohmann Dual, LD, n = 844); and 3. cockerels of a native breed (Rhinelander, RL, n = 458). Chicks were raised under identical conditions and marked individually to compare focus and random sampling methods for weighing birds weekly. Because chicks of dual-purpose origins are usually raised mixed-sex, cockerels and pullets were weighed and observed together until sexes the were identifiable at week 10 of their life. During the 10th to 20th week of life, investigations were continued on 100 cockerels per genotype. Key figures for growth performance, such as feed conversion ratio (FCR) and European production efficiency factor (EPEF), were also calculated at weekly intervals. LD cockerels showed considerable growth performance (p < 0.001 compared to LB, RL, 2 kg at 9 weeks), whereas LB reached a live weight of 2 kg at 13 weeks and RL at 15 weeks of age. Genotype-dependent differences were also evident, with favorable FCR and EPEF for LD, intermediate for LB, and unfavorable for RL (all p < 0.001). The results of the FCR and EPEF suggest that cockerels should be slaughtered around week 8 of life, although only the carcass of the LD might be marketable. Thus, the optimal time of slaughter based on production parameters such as FCR and EPEF is different from the time when the animal reaches a marketable 2 kg live weight. Animal-based welfare indicators revealed that the RL are not adapted to production environments, including those that are extensive. Further research aimed at adapted feed management, including better FCR, and animals adapted to the respective production environments is necessary to improve alternative poultry production in the future.