Reproductive season and male effect on quantitative and qualitative traits of individually collected Muscovy duck (Cairina moschata) semen

Identification of potential candidate genes and regulatory pathways related to reproductive capacity in hypothalamus and pituitarium of male ducks (Anas platyrhynchos) by differential transcriptome analysis

The improvement of reproductive capacity of poultry is important for the poultry industry. The existing studies on reproductive capacity mainly focus on the testis tissue, but few reports on regulationary effect of brain neuroendocrime on reproductive capacity have been available. The hypothalamus-pituitarium-gonad (HPG) axis is an important pathway regulating spermatogenesis and sexual behavior. This study analyzed the gene expression in the hypothalamus and pituitary tissues of male ducks in high-semen-quality group (DH), low-semen-quality group (DL), and non-response group (DN) by RNA-sequencing. A total of 1980 differentially expressed genes (DEGs) were identified, and significantly less DEGs were found in pituitary gland than in hypothalamus. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses showed that these DEGs were mainly enriched in nerve-related and synapse-related biological processes, mitochondrial inner membrane formation pathway, and ribosome structure pathway. Notably, the neuroactive ligand-receptor interaction pathway significantly enriched in all three comparisons (DH vs. DL, DH vs. DN, and DL vs. DN) was related to different reproductive performance such as semen quality and sexual response. Furthermore, six genes, including POMC, CPLX2, HAPLN2, EGR4, TOX3, and MSH4, were identified as candidate genes regulating reproductive capacity. Our findings provide new insights into the regulation mechanisms underlying the reproductive performance of male poultry, and offer a valuable reference for duck breeding programs aimed at promoting reproductive capacity.

A comparative proteomic study of high and low semen quality seminal plasma in drakes

Semen quality is the most important indicator in evaluating drake fecundity. At present, the low semen quality has become a major factor restricting the development of artificial insemination (AI) technology in ducks. Numerous studies have indicated that seminal plasma proteins play a crucial role in semen quality, but the mechanism of seminal plasma proteins regulating semen quality of drakes remains unclear. Thus, the objective of this study was to identify seminal plasma proteins associated with semen quality by comparing the seminal plasma proteomic profile of drakes with high-quality semen (HQS) and low-quality semen (LQS). Using a label-free MS-based method, a total of 745 seminal plasma proteins were identified. Of these, 55 differentially expressed proteins (DEPs) were identified (40 up-regulated and 15 down-regulated). Gene Ontology (GO) analysis showed that the DEPs were mainly enriched in transmembrane transport, extracellular matrix structural constituent, transferase activity, transferring acyl groups other than amino-acyl groups, transmembrane transporter activity, and integral component of membrane (P < 0.05). Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis indicated that the DEPs were significantly enriched in apoptosis, tyrosine metabolism, glycerophospholipid metabolism, and sulfur metabolism pathways (P < 0.05). Moreover, through protein-protein interaction (PPI) network analysis, eight potential candidate proteins were identified, including P19140 (Alpha-enolase), R0KUV7 (Calreticulin), R0K3X3 (Solute carrier family 2, facilitated glucose transporter member 5), R0L6V0 (Proteasome subunit beta), R0JKW0 (Cytochrome c), R0JMC5 (Tubulin alpha chain), R0LCK1 (Cathepsin C), and R0JUP6 (Cathepsin D), which could play crucial roles in semen quality. Notably, further analysis demonstrated that key protein P19140 (Alpha-enolase) might can control the semen quality of drakes by regulating the expression of proteins related to apoptosis pathway. This study is the first systematically comparing the seminal plasma proteome of drakes exhibiting high and low semen quality. These results provide novel insights into the mechanisms regulating semen quality of drakes.

Semen characteristics of ganders kept as genetic resources conservation program

The creation of genetic reserves of domesticated animal species and breeds almost become a necessity in the recent years, but there is a question what is the value of semen of males kept ex situ in vivo as gene conservation flocks. Presented studies assessed the response to semen collection by dorso-abdominal massage and the quantitative and qualitative semen characteristics of six goose breeds (Pomorska, Garbonosa, Kuban, Landes, Roman and Slovakia) covered by the genetic resources' protection program. Fourteen semen collection attempts were performed per male. In each breed there were ganders with low and high sensitivity to massage. The most positive reactions were stated in Pomorska ganders (67.9%), and the least in Kuban breed (52.60%). Individual male evaluation showed that only in three breeds (Pomorska, Garbonosa and Kuban) there were individuals showing 100% susceptibility to semen collection, in some breeds only 1-4 positive reactions (ending with ejaculation) were noted. Results obtained indicated breed and male effect on analyzed semen traits, with the exception of sperm motility. The highest number of live normal sperm (44.2% on average), sperm concentration (530 x10⁶ mL^-1 ), the highest Semen Quality Factor (92.9) and sperm motility (50.30%) were found in semen of Kuban ganders, while the lowest values of these traits (28.7%; 230 x10⁶ mL^-1 ; 11.4, respectively) in Slovakia ganders. The lowest sperm motility (38.3%) was observed in ganders of Roman breed, but comparing to the other breeds existing differences were not significant. Significant differences in sperm morphology between individual ganders were also observed.

Effect of prooxidants and chelator Desferal on the oxidative status and sperm motility of Muscovy semen

This study aimed to establish the sensitivity of Muscovy duck semen to oxidative stress (OS) and the effect of Desferal, applied as an antioxidant. The effect of three prooxidant systems in presence and absence of Desferal were tested on the motility and kinetic parameters (determined using CASA system), as well as the level of lipid peroxidation (LPO) and glutathione (tGSH) of Muscovy semen. The semen was diluted (1:3 v/v) with four extenders (saline solution, IMV Canadyl, HIA-1, and AU) and stored at 4 °C for 6 h. The cooled semen was divided into aliquots (50 × 106 sperm cells/mL), which were incubated at 37 °C for 30 min with one of the following prooxidative agents: ferrous sulfate (FeSO4, 0.1 mM), hydrogen peroxide (H2O2, 1 mM), and Fenton system (FeSO4(Fe2+), 0.1 mM + H2O2, 1 mM), in the presence or absence of Desferal (0.1 mM). The addition of FeSO4 + H2O2 or FeSO4 regardless of the used extender, as well as the addition of H2O2 to the diluted semen with saline solution significantly increased the levels of LPO (P < 0.05). With the lowest prooxidant effect was H2O2. The application of Desferal reduced significantly (P < 0.05) the LPO levels induced by FeSO4 + H2O2 or FeSO4 and in a weaker degree by H2O2. Among all prooxidants, FeSO4 + H2O2 decreased in the greatest extent the tGSH concentration in semen diluted with each used extenders in comparison to the relevant control. The addition of Desferal in semen diluted with HIA-1 extender and incubated with FeSO4, and H2O2, showed the best restoration of tGSH level, close to that of respectively controls. The studied prooxidants significantly reduced total, progressive, and kinetic sperm motility (P < 0.05). Although the inclusion of Desferal reduced the sperm OS, it did not improve the impaired by OS sperm motility.

Improving Gander Reproductive Efficacy in the Context of Globally Sustainable Goose Production

The goose is a popular poultry species, and in the past two decades the goose industry has become highly profitable across the globe. Ganders low reproductive performance remains a barrier to achieving high fertility and hatchability in subsequent flocks. To address the global demand for cheaper animal protein, various methodologies for improving avian (re)production should be explored. A large amount of literature is available on reproduction traits and techniques for commercial chicken breeder flocks, while research on improved reproduction in ganders has been carried out to a lesser extent. The present review aims to provide a comprehensive literature overview focusing on recent advancements/techniques used in improving gander reproductive efficacy in the context of ensuring a globally sustainable goose industry.

Characteristics of semen collected from gander included in the genetic resources conservation program

Conservative breeding ex situ in vivo is one of the most popular methods of creating genetic reserves. Unfortunately, keeping animals in small closed populations leads to inbreeding which reduces their reproductive capacity. The aim of the study was to characterize the sperm quality of 6 genetic groups of geese (northern and southern breeds) kept in Poland for many generations as genetic reserve flocks. Each breed was represented by 10 randomly selected 1-yr-old ganders, semen was collected 14 times, individually from each male, and the number of positive reactions (ended with ejaculation), semen volume, sperm concentration, and morphology were assessed. The obtained results showed a significant difference between breeds and individuals of the same group, both in males’ reaction and semen quantitative and qualitative traits. From the northern breeds 193 ejaculates were obtained in total (i.e., 45.9% of all attempts), from the southern breeds 242 ejaculates (57.6%). The volume of single ejaculate varied from 0.01 mL (one drop allowing only histological smear and sperm morphology evaluation) to 0.65 mL; sperm concentration varied from 23.0 × 10⁶mL⁻¹ to 2376.0 × 10⁶mL⁻¹; the amount of total live sperm was at a similar level in all breeds (89.6%–97.7%), while live normal cells ranged between 15.2% and 67.9% depending on breed and individuals. When keeping the genetic reserves ex situ in vivo, attention should be paid to the quality of semen and males that are poor in this respect should be eliminated, in order not to lead to an excessive weakening of the reproductive capacity of the flocks covered by the genetic resources protection program.