Feeding programs promoting daily feed intake stability in rabbit males reduce sperm abnormalities and improve fertility

The Improvement of Semen Quality by Dietary Fiber Intake Is Positively Related With Gut Microbiota and SCFA in a Boar Model

Although fiber-rich diets have been positively associated with sperm quality, there have not been any studies that have examined the effects of dietary fiber and its metabolites on sperm quality in young or pre-pubescent animals. In this study, we aimed to explore the effect of dietary fiber supplementation on semen quality and the underlying mechanisms in a boar model. Sixty purebred Yorkshire weaning boars were randomly divided into the four groups (T1–T4). Groups T1, T2, and T3 boars were fed diets with different levels of fiber until reaching 160 days of age and were then fed the same diet, while group T4 boars were fed a basal diet supplemented with butyrate and probiotics. Compared with T1 boars, sperm motility and effective sperm number were significantly higher among T3 boars. Meanwhile, at 240 days of age, the acetic acid and total short-chain fatty acid (SCFA) contents in the sera of T3 and T4 boars were significantly higher than those in T1 boars. The abundance of microbiota in T2 and T3 boars was significantly higher than that in T1 boars (P < 0.01). Moreover, dietary fiber supplementation increased “beneficial gut microbes” such as UCG-005, Rumenococcus, Rikenellaceae_RC9_gut_group and Lactobacillus and decreased the relative abundance of “harmful microbes” such as Clostridium_sensu_stricto_1, Romboutsia and Turicibacter. Collectively, the findings of this study indicate that dietary fiber supplementation improves gut microbiota and promotes SCFA production, thereby enhancing spermatogenesis and semen quality. Moreover, the effects of dietary fiber are superior to those of derived metabolites.

Effect of early development on semen parameters and lifespan of rabbit males selected by high growth rate

Life history theory suggests that different body development dynamics may influence survival and future reproductive performance of organisms. The present work studied how these dynamics could influence seminal traits and lifespan of rabbit males selected for growth rate and intended for AI. To achieve this goal, a total of 550 rabbit males were controlled from birth, evaluated both during the testing phase (four consecutive weeks after reaching 147 days of life) and the productive phase (377 of them from the end of the testing phase until 2 years of life). In order to obtain individuals with different body development dynamics, we pre-selected males based on their live weight (LW) at 0, 28, 63 and 147 days and on their average daily gain (ADG) between each period (0-28, 28-63 and 63-147 days). Libido and main seminal traits (semen volume, motility, concentration, and production, as well as normal apical ridge and abnormalities of spermatozoa) were controlled during the testing phase. Semen volume, motility and concentration were subsequently controlled during the productive phase, as well as the length of the male life, calculated as the number of days a rabbit was present at the farm between age 147 and day of death, culling or censoring; set to 2 years of life). The birth weight, the ADG between 0 and 28 days and between 28 and 63 days were positively related to some seminal parameters measured during the testing phase (semen volume, concentration, production and motility; P < 0.05), while the ADG between 63 and 147 days was negatively related to the seminal productivity throughout the productive life of the males (an increment of 10 g per day on ADG reduced the number of profitable ejaculates by 4.9%; P < 0.05). In addition, a higher growth between 0 and 28 and between 63 and 147 days increased the risk of death or culling of males during the productive phase (P < 0.05). In conclusion, an adequate body development early in life seems to have a positive effect on the degree of sexual maturity with which male rabbits begin their reproductive life, but reaching the reproduction onset with excessive weight can reduce their reproductive performance and lifespan.

The effects of dietary restriction and administration of β-glucan from Euglena gracilis on the sperm characteristics and reproductive organs of rats

The aim of this study was to demonstrate the possible individual and/or synergistic effects of β-glucan and dietary restrictions on the reproductive parameters of rats. For this purpose, forty male Sprague-Dawley rats were randomly divided into four equal groups (n = 10 per group). The first group was the control, the second group was kept under dietary restriction (DR), the third group was kept under a dietary restriction and given β-glucan (DR + βG) and the fourth group was supplemented only with β-glucan (βG; 20 mg/kg) intragastrically for 14 days. Motility, vitality and morphology of spermatozoa, reproductive organ weights (testis, vesicula seminalis and epididymis) and seminiferous tubule diameters were evaluated in experimental rats. β-glucan had excellent effects on motility, live spermatozoa rate and the acrosome integrity when compared to the control group (p < 0.05). We also observed that β-glucan administration to rats having dietary restriction could improve sperm motility and acrosome integrity (p < 0.05). While the β-glucan improved seminiferous tubule diameter (p < 0.05), weights of the reproductive organs did not change positively as a result. This study demonstrated that β-glucan treatment significantly improved some spermatological characteristics in rats. Therefore, treatment with β-glucan could be used for its positive effects on motility, spermatozoa vitality rate and acrosome integrity for infertile men.

Rabbit seminal plasma proteome: The importance of the genetic origin

The present study was conducted to characterise rabbit seminal plasma proteins (SP proteins) focusing on the influence of the genetic origin and seasonality. In addition, β-NGF protein quantity in SP was determined. Semen samples were recovered from January to December 2014 using 6 males belonging to genotype A and six from genotype R. For each genotype, one pooled sample at the beginning, middle and end of each season was selected to develop the experiment. A total of 24 pools (3 for each season and genetic line) were analysed. SP proteins of the two experimental groups were recovered and subjected to in-solution digestion nano LC-MS/MS and bioinformatics analysis. The resulting library included 402 identified proteins validated with ≥95% Confidence (unused Score ≥ 1.3). These data are available via ProteomeXchange with identifier PXD006308. Only 6 proteins were specifically implicated in reproductive processes according to Gene Ontology annotation. Twenty-three proteins were differentially expressed between genotypes, 11 over-expressed in genotype A and 12 in genotype R. Regarding the effect of season on rabbit SP proteome, results showed that there is no clear pattern of protein variation throughout the year. Similar β-NGF relative quantity was observed between seasons and genotypes. In conclusion, this study generates the largest library of SP proteins reported to date in rabbits and provides evidence that genotype is related to a specific abundance of SP proteins.