This study was conducted to elucidate the molecular mechanisms underlying heat stress (HS)-induced abnormal egg-laying in laying hens. Hy-Line brown laying hens were exposed to HS at 32 °C or maintained at 22 °C (control) for 14 days. In addition, granulosa cells (GCs) from preovulatory follicles were subjected to normal (37 °C) or high (41 °C or 43 °C) temperatures in vitro. Proliferation, apoptosis, and steroidogenesis were investigated, and the expression of estrogen and progesterone synthesis-related genes was detected. The results confirmed that laying hens reared under HS had impaired laying performance. HS inhibited proliferation, increased apoptosis, and altered the GC ultrastructure. HS also elevated progesterone secretion by increasing the expression of steroidogenic acute regulatory protein (StAR), cytochrome P450 family 11 subfamily A member 1 (CYP11A1), and 3b-hydroxysteroid dehydrogenase (3β-HSD). In addition, HS inhibited estrogen synthesis in GCs by decreasing the expression of the follicle-stimulating hormone receptor (FSHR) and cytochrome P450 family 19 subfamily A member 1 (CYP19A1). The upregulation of heat shock 70 kDa protein (HSP70) under HS was also observed. Collectively, laying hens exposed to high temperatures experienced damage to follicular GCs and steroidogenesis dysfunction, which reduced their laying performance. This study provides a molecular mechanism for the abnormal laying performance of hens subjected to HS.

Background: Increasing the polyunsaturated fatty acid (PUFA) content and decreasing the saturated fatty acid (SFA) content of mutton can help to improve its nutritional value for consumers. Several laboratories have evaluated the effects of vitamin E on the fatty acid (FA) composition of muscle in sheep. However, little information is available on wool sheep, even though wool sheep breeds are an important source of mutton, especially in northern China where sheep are extensively farmed. The present study was designed to address the effects of vitamin E on muscle FA composition in male Aohan fine-wool sheep. Methods: Forty-two male Aohan fine-wool lambs (5 mo old) with similar initial body weight were randomly divided into seven groups and fed diets supplemented with 0 (control group), 20, 100, 200, 1,000, 2,000, or 2,400 IU/sheep/d vitamin E for 12 mo. Three lambs from each group were slaughtered to measure vitamin E and FA content in the longissimus lumborum (LL) and gluteus medius (GM) muscles. Results: Vitamin E concentrations in the LL and GM increased significantly after 12 mo of vitamin E supplementation (P < 0.05). However, this increase did not occur in a dose-dependent manner because the muscle vitamin E concentration was highest in the 200 IU/sheep/d group. Dietary vitamin E supplementation also caused a significant reduction in SFA content and an increase in monounsaturated FA (MUFA) content in the LL and GM (P < 0.05). All six doses of vitamin E significantly increased cis 9 trans 11-conjugated linoleic acid (c 9t 11-CLA) content in the LL compared with the control group (P < 0.05). Conclusions: Dietary supplementation with vitamin E increased muscle vitamin E content and improved the nutritional value of mutton by decreasing SFA content and increasing MUFA and c 9t 11-CLA contents in Aohan fine-wool sheep. These effects were greatest in sheep fed a diet containing 200 IU/sheep/d vitamin E.

The objective of this study was to investigate the effects of sex on meat quality and the composition of amino and fatty acids in the breast muscles of White King pigeon squabs. Untargeted metabolomics was also conducted to distinguish the metabolic composition of plasma in different sexes. Compared with male squabs, female squabs had greater intramuscular fat (IMF) deposition and lower myofiber diameter and hydroxyproline content, leading to a lower shear force. Female squabs also had higher monounsaturated fatty acid and lower n-6 and n-3 polyunsaturated fatty acid proportions in the breast muscle, and had greater lipogenesis capacity via upregulation of PPARγ, FAS and LPL gene expression. Moreover, female squabs had lower inosine 5'-monophosphate, essential, free and sweet-tasting amino acid contents. Furthermore, Spearman's correlations between the differential plasma metabolites and key meat parameters were assessed, and putrescine, N-acetylglutamic acid, phophatidylcholine (18:0/P-16:0) and trimethylamine N-oxide were found to contribute to meat quality. In summary, the breast meat of male squabs may have better nutritional value than that of females, but it may inferior in terms of sensory properties, which can be attributed to the lower IMF content and higher shear force value. Our findings enhance our understanding of sex variation in squab meat quality, providing a basis for future research on pigeon breeding.

In the past two decades, the high demand of and significance of poultry meat have promoted the development of the goose industry. Despite the continuous expansion of the goose breeding scale and the generation of large economic benefits by the goose industry, low reproductive efficiency remains a barrier to limit vigorous development of the goose industry. Poor reproductive efficiency can be attributed to breeding seasonality, strong broody behavior, and poor semen quality. Based on the reproductive endocrine regulation mechanism of geese, an overview of past studies that have developed various methods to achieve a significant improvement in goose reproductive performance including physical facilities for artificial illumination control and dietary nutrition manipulation to improve breeder reproductivity, and artificial incubation equipment and technology for better hatchability. The most recent advances utilize immunoneutralization to regulate critical hormones involved in goose reproduction. This review provides new information for industry and academic studies of goose breeding.