Comparative assessment of growth performance of indigenous and cross-bred calves subjected to combined stressors (heat and nutritional).

This study evaluated the impact of combined stressors (heat and nutritional stresses) on the growth and adaptive capability of Sahiwal (SW) and Karan Fries (KF) calves during the summer season. Calves in each breed were randomly divided into four groups. In SW breed the groupings were as follows: SWC (n = 4; Sahiwal Control); SWHS (n = 4; Sahiwal Heat Stress); SWNS (n = 4; Sahiwal Nutritional Stress) and SWCS (n = 4; Sahiwal Combined Stresses). Likewise, in the KF breed, KFC (n = 4; Karan Fries Control); KFHS (n = 4; Karan Fries Heat Stress); KFNS (n = 4; Karan Fries Nutritional Stress), and KFCS (n = 4; Karan Fries Combined Stresses). Control (C) and Heat Stress (HS) calves were fed ad libitum while Nutritional Stress (NS) and Combined Stresses (CS) calves were fed restricted feed (50% of C calves of respective breed) to induce nutritional stress in both the breeds. SWHS, SWCS, KFHS, and KFCS were exposed to summer heat stress from 1000 to 1600 h. All growth and adaptation variables were recorded at fortnightly intervals. Respiration rate, pulse rate, and rectal temperature during the afternoon were significantly (P < 0.01) higher in the CS group in both breeds. Further, CS had significantly (P < 0.05) higher plasma growth hormone and cortisol levels. Insulin-like growth factor-1, Triiodothyronine, and Thyroxine levels significantly decreased (P < 0.05) in the CS group in both breeds. Interestingly, heat stress didn't affect SWHS and KFHS bodyweight, however, a significant (P < 0.05) decrease in body weight of SWCS and KFCS was observed when compared with C. Hepatic mRNA expression of growth hormone, insulin-like growth factor-1, and growth hormone receptor significantly (P < 0.05) varied when compared between C and CS groups in both the breeds. The overall magnitude of stress was more pronounced in KF compared to the SW breed. This study concludes that when two stressors occur concurrently, they may have a greater influence on the adaptive capability of calves. Further, SW had better tolerance levels than KF, confirming the indigenous breed's superiority over cross-bred.

Time and dose-dependent effect of preconditioning with sodium nitroprusside (SNP) and 3-morpholinosydnonimine (SIN-1) on post-thaw semen quality of Karan-Fries (KF) bulls.

A novel strategy, focused on the induction of sub-lethal oxidative stress to optimize sperm cryosurvival, has been used before cryopreservation. The present study compared the effect of preconditioning with various concentrations of nitric oxide-donor (sodium nitroprusside, SNP) and peroxynitrite-generator (3-morpholinosydnonimine, SIN-1) on in vitro sperm functions and lipid peroxidation status (LPO) of cryopreserved Karan-Fries (KF) crossbred bull semen. To optimize the concentration of additives, spermatozoa obtained from 36 ejaculates were supplemented with different concentrations of SNP (0.01, 0.05, 0.1 µM) and SIN-1 (80, 160, 200 µM) versus control in the extender. The post-freezing sperm motility and viability were greater (p < 0.05) in 0.1 µM SNP and 80 µM SIN-1 in comparison to other concentrations used. Furthermore, the spermatozoa obtained from 48 ejaculates were supplemented with 0.1 µM SNP and 80 µM SIN-1 in the extender. A significant increase (p < 0.05) was observed in progressive motility, viability and membrane integrity in SNP and SIN-1 treated extender at 24 h, 15 days, and 2-month post-cryopreservation (PC) periods. There was no significant difference in sperm abnormality in the extended groups and the control group. The seminal plasma of SNP-treated extender had less (p < 0.05) lipid peroxidation as compared to SIN-1 treated and control groups. In post-thaw semen, both SNP and SIN-1 showed a higher (p < 0.05) proportion of acrosome intact (FITC-PNA) sperm with a greater decrease (p < 0.05) in membrane scrambling and lipid peroxidation. SNP and SIN-1 improved (p < 0.05) the proportion of sperm with higher mitochondrial membrane potential (Δψm) as compared to the control. In conclusion, it seems that the preconditioning of SNP and SIN-1 at lower doses may have beneficial effects on post-thawed crossbred bull sperm quality.

Role of probiotics in ruminant nutrition as natural modulators of health and productivity of animals in tropical countries: an overview.

Given the ever-growing population in the developing countries located in the tropics of Asia, Africa, South America, and the Caribbean, the demand for products of animal origin has increased. Probiotics have proven to be a substantial substitute for antibiotics used in the animal diet and thus gained popularity. Probiotics are live and non-pathogenic microbes commercially utilized as modulators of gut microflora, hence exerting advantageous effects on the health and productivity of animals in tropical countries. Probiotics are mainly derived from a few bacterial (Lactobacillus, Enterococcus, Streptococcus, Propionibacterium, and Prevotella bryantii) and yeast (Saccharomyces and Aspergillus) species. Numerous studies in tropical animals revealed that probiotic supplementation in a ruminant diet improves the growth of beneficial rumen microbes, thus enhancing nutrient intake and digestibility, milk production, and reproductive and feed efficiency, along with immunomodulation. Furthermore, probiotic applications have proven to minimize adverse environmental consequences, including reduced methane emissions from ruminants' anaerobic fermentation of tropical feedstuffs. However, obtained results were inconsistent due to sources of probiotics, probiotic stability during storage and feeding, dose, feeding frequency, and animal factors including age, health, and nutritional status of the host. Furthermore, the mechanism of action of probiotics by which they exhibit beneficial effects is still not clear. Thus, more definitive research is needed to select the most effective strains of probiotics and their cost-benefit analysis. In this review article, we have briefly explained the impact of feeding probiotics on nutrient intake, digestibility, reproduction, growth efficiency, productivity, and health status of tropical ruminant animals.