Forced-Molting methods and their effects on the performance and egg quality of japanese quails (Coturnix japonica) in the second laying cycle

Transcriptomic analysis of mechanism underlying the effect of induced molting on semen quality and reproductive performance in aged Houdan roosters

The reproductive performance of breeder roosters has significant economic importance in the poultry industry. Breeder roosters have severely reduced semen quality with age and will be at risk of culling in the following years. In order to extend the use of breeder roosters, we drew on the induced molting model of hens and selected 35 Houdan roosters aged 50 wk for induced molting. By comparing the body weight, testicular weight, semen quality, and reproductive performance before and after induced molting, we found that induced molting could restore the body weight and testicular weight to the levels before molting (P > 0.05). At the same time, it significantly improved sperm motility (P < 0.05) and also improved reproductive performance such as fertilization rate and hatching rate. To further reveal the mechanism underlying the effects of induced molting on semen quality and reproductive performance in aged Houdan roosters, we collected testes from 3 periods: 1 d before fasting (F0), 15 d after fasting (F15), and 32 d after recovery feeding (R32) for transcriptome sequencing analysis. A total of 5,671 genes were detected in F0, F15, and R32, and trend analysis of the 5,671 differential genes showed 2 significant trends (profile 5 and profile 2). KEGG enrichment analysis of the genes in the 2 profiles, revealed significantly enriched pathway regulation of actin cytoskeleton. In the regulation of actin cytoskeleton pathway, we found a protein kinase gene (SRC) and a senescence gene (ROCK2). SRC was highly expressed at F15, leading to the phosphorylation of key substrates, which in turn disrupted the Sertoli cell spermatid connection and the spermiogenesis process, resulting in no mature spermatozoa produced from F15, SRC expression was inhibited at R32, the expression level was reduced, and mature spermatozoa reappeared. The senescence gene ROCK2 was highly expressed at F15 compared to F0 and R32, which may have been responsible for inducing senescence atrophy in the testes.

Interaction Between Cecal Metabolites and Liver Lipid Metabolism Pathways During Induced Molting in Laying Hens

Moult is a normal physiological phenomenon in poultry. Induced molting (IM) is the most widely used and economical molting technique. By inducing moult, the laying hens can grow new feathers during the next laying cycle and improve laying performance. However, the lack of energy supply has a huge impact on both the liver and intestines and acts on the intestines and liver through the “gut-liver axis”. More importantly, lipid metabolism in the liver is closely related to the laying performance of laying hens. Therefore, in this study, cecal metabolites and liver transcriptome data during IM of laying hens at the late stage of laying (stop feeding method) were analyzed together to reveal the regulatory mechanism of “gut-liver axis” affecting the laying performance of laying hens from the perspective of lipid metabolism. Transcriptome analysis revealed that 4,796 genes were obtained, among which 2,784 genes had significant differences (p < 0.05). Forty-nine genes were associated with lipid metabolism, and five core genes (AGPAT2, SGPL1, SPTLC1, PISD, and CYP51A1) were identified by WGCNA. Most of these differential genes are enriched in steroid biosynthesis, cholesterol metabolism, drug metabolism—cytochrome P450, synthesis and degradation of ketone bodies, PPAR signaling pathway, and bile secretion. A total of 96 differential metabolites were obtained by correlating them with metabolome data. Induced moult affects laying performance by regulating genes related to lipid metabolism, and the cecal metabolites associated with these genes are likely to regulate the expression of these genes through the “enterohepatic circulation”. This experiment enriched the theoretical basis of induced moult and provided the basis for prolonging the feeding cycle of laying hens.

Age-related declines in ejaculate quality and sperm kinematics vary among strains of Japanese Quail (Coturnix japonica)

For successful breeding programs, it is important to quantify the useful period of a male's reproductive life and it is often done simply by measurement of semen quality. This information is lacking for Japanese quail so we tested whether there is a decline in ejaculate quality and sperm kinematics with age, and whether the decline varies among strains. Nine males (n = 9) from each of 5 strains (A, B, C, D and E) were subjected to 4 semen collections (n = 16 per male) at 8, 16, 26 and 36 weeks of age. Ejaculate volume, sperm concentration and total sperm per ejaculate were measured, and sperm kinematics were analysed using a Sperm Class Analyser (SCA^® ). There was a significant effect of age for ejaculate volume, total sperm per ejaculate and per cent medium sperm. The effect of the interaction between age and strain was significant for percent progressive motile sperm, percent rapid sperm, velocity curvilinear, velocity straight line, velocity average path, linearity, straightness and beat cross frequency. Ejaculate volume peaked at Week 26 in all strains, while peak values for sperm concentration and total sperm per ejaculate were observed at Week 16 for most strains. There were declines in percent motile sperm, progressive motile sperm and rapid sperm, and in velocity curvilinear velocity, velocity straight line and velocity average path, by Week 16 for most strains. Linearity declined by Week 26 in some strains, and all strains showed a significant decline in beat cross frequency by that age. In conclusion, the ability of CASA to detect age-related changes in sperm kinematics makes it a valuable tool for identifying the best males and thus improving quail flock fertility. It is essential that breeders understand that age affects both sperm production and sperm kinematics, and that the changes vary with strain.

Alternative forced-molting methods in japanese quails

SUMMARY The aim of this study was to evaluate the effects of different forced-molting methods on the performance and quality of laying quail eggs. The experiment was conducted in a conventional shed for quails and lasted 115 days. 480 Japanese quails at an initial age of 52 weeks were used. The following treatments were evaluated: total feed fasting (control treatment); corn and soybean bran diet; high- zinc diet (7,300 ppm); wheat bran diet; and ground corn diet. A fully randomized experimental outline was used with 5 treatments and 4 repetitions. Each lot was formed by 24 quails with a total of 480 birds. Performance (production and egg weights, feed intake, feed conversion ratio per kg egg mass and per dozen eggs, viable eggs and egg viability) and egg quality (eggshell thickness and yield, specific weight and Haugh unit) were evaluated. Treatment differences were compared using the Scott-Knott test (5%). Wheat bran and high- zinc diets yielded poorer averages of egg production and feed conversion ratioper dozen eggs. Studied treatments had no influence on egg quality. Hence, we can conclude that corn- only or corn and soybean bran only feeds can be adopted as forced molting methods in Japanese quails instead of traditional fasting methods.