Heat stress can impair the general health of rabbit bucks by disturbing physiological homeostasis with negative consequences in animal welfare and remarkable decline in reproductive performance. Selenium (Se) can control a number of vital biological processes. Thus, the effects of organic selenium (OSe) supplementation on the blood metabolites, redox status, semen quality, testicular histology, seminal plasma protein profile, and fertility of rabbit bucks kept under natural heat stress conditions were studied. Adult V-line male rabbits were fed a basal diet supplemented with 0.3 mg OSe/kg dry matter (DM) diet (OSe, n = 9) or not (control, CON, n = 9) for 12 weeks. The results showed that rabbits fed the OSe diet had 73.68 and 68.75% higher (P < 0.05) OSe concentrations in the blood serum and seminal plasma, respectively, than rabbits fed the CON diet. The OSe diet significantly decreased the rectal temperature and respiration rate and significantly increased the blood serum concentrations of total protein, albumin, glucose, and glutathione peroxidase compared to the CON diet. Rabbits fed the OSe diet had lower reaction times (12.53 vs. 5.84 s, ± 0.79, P < 0.01) and higher total functional sperm counts (116.74 vs. 335.23 × 10 6 /ml, ± 24.68, P < 0.001) and percentages of integrated sperm membranes (60.38 vs. 79.19%, ± 1.69, P < 0.01) than rabbits fed the CON diet. Rabbits fed the OSe diet had higher (P < 0.01) contents of seminal plasma total protein, albumin, alanine transaminase, fructose, and total antioxidant capacity and lower (P < 0.001) malondialdehyde (MDA) levels than those fed the CON diet. Rabbits fed the OSe diet had sperm cells with higher levels of integrated DNA than those fed the CON diet. The seminal plasma of rabbits fed the OSe diet contained four new proteins, with molecular weights of 19.0, 21.5, 30.0, and 44.0 kDa. The kindling rates, litter size, and weight at birth of females mated with males fed the OSe diet were significantly higher than those of females mated with males fed the CON diet. In summary, the inclusion of 0.3 mg OSe/kg DM diet of naturally heat-stressed rabbit bucks countered the negative impacts of elevated environmental temperature on physiological homeostasis, semen quality, and fertility.

Two types of modified nano-montmorillonite (MNM) were developed by ion-exchange reactions using two different surfactants; sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CETAB), to prepare MNMSDS and MNMCETAB, respectively. Both MNM types were on the nano-scale and had higher cation-exchange capacity values than NM clay. The MNMCETAB had the highest zeta potential (−27 mV) compared with the other clays. Effects of MNM types on in vitro ruminal batch culture fermentation, nutrient degradability, and methane (CH4) emission compared with monensin were evaluated in vitro using a semi-automatic gas production system. The experimental treatments were the control (0 supplementations), monensin (40 mg/kg DM), and NM (5 g NM/kg DM), and two levels of MNMSDS and MNMCETAB were supplemented at 0.05 (low) and 0.5 (high) g/kg DM to the control basal feed substrate. Among the experimental treatments, the high dose of both MNM types reduced (p < 0.01) CH4 production and ammonia concentrations compared with the control, while only MNMCETAB treatment tended to increase (p = 0.08) the truly degraded organic matter compared with monensin. All MNM treatments increased (p < 0.01) acetate molar proportions compared with monensin. The high MNMCETAB increased (p < 0.01) the in vitro ruminal batch culture pH compared with the control and monensin. The MNMCETAB supplemented at 0.5 g/kg DM is the most efficient additive to reduce CH4 emission with the advantage of enhancing the in vitro nutrient degradability of the experimental feed substrate. These results indicated that MNM could modulate the in vitro ruminal fermentation pattern in a dose- and type-dependent manner.

A synbiotic comprising Saccharomyces cerevisiae yeast (SCY) and Moringa oleifera leaf extract (MOLE) has been encapsulated using nanotechnology. This duo is used as a dietary supplement for growing rabbits. Physicochemical analyses, in vitro antimicrobial activity, and gastrointestinal system evaluation were used to evaluate the quality of the nanofabricated synbiotic. The in vivo study was conducted using 40-day-old male growing rabbits (n = 16 rabbits/group) to evaluate the effect of the nanofabricated synbiotic on the health and growth performance of examined rabbits. Rabbits were equally allocated into four groups; (a) NCS, which received a basal diet supplemented with a noncapsulated 11 × 1012 CFU SCY + 0.15 g MOLE/kg diet, (b) LCS: those receiving a nanoencapsulated 5.5 × 1012 CFU SCY + 0.075 g MOLE/kg diet, (c) HCS: those receiving an 11 × 1012 CFU SCY + 0.15 g MOLE/kg diet, and (d) CON: those receiving a basal diet without treatment (control). The treatments continued from day 40 to day 89 of age. During the experimental period, growth performance variables, including body weight (BW), feed consumption, BW gain, and feed conversion ratio were recorded weekly. Blood samples were collected on day 40 of age and immediately before the start of the treatments to confirm the homogeneity of rabbits among groups. On day 89 of age, blood samples, intestinal, and cecal samples were individually collected from eight randomly selected rabbits. The size and polydispersity index of the nanofabricated synbiotic were 51.38 nm and 0.177, respectively. Results revealed that the encapsulation process significantly improved yeast survival through the gastrointestinal tract, specifically in stomach acidic conditions, and significantly increased in vitro inhibitory activities against tested pathogens. Furthermore, treatments had no negative effects on hematobiochemical variables but significantly improved levels of blood plasma, total protein, and insulin-like growth factor-l. Compared to the CON, NCS, and LCS treatments, the HCS treatment increased the amount of intestinal and cecal yeast cells (p < 0.05) and Lactobacillus bacteria (p < 0.05) and decreased number of Salmonella (p < 0.05) and Coliform (p = 0.08) bacteria. Likewise, both LCS and HCS significantly improved the small intestine and cecum lengths compared to CON and NCS. The HCS treatment also significantly improved BW gain and feed conversion compared to CON treatment, whereas the NCS and LCS treatments showed intermediate values. Conclusively, the nanoencapsulation process improved the biological efficiency of the innovative synbiotic used in this study. A high dose of encapsulated synbiotic balanced the gut microflora, resulting in the growth of rabbits during the fattening period.

A symbiotic consists of Saccharomyces cerevisiae yeast, SCY, and Moringa oleifera leaf extract, MOLE, encapsulated with alginate was fabricated as a dietary supplement for growing rabbits.