Ramifications of Heat Stress on Rabbit Production and Role of Nutraceuticals in Alleviating Its Negative Impacts: An Updated Review.

Heat stress has become a widespread concern worldwide, which is a major environmental stress that causes substantial economic loss in the rabbit industry. Compared to other agricultural animals, rabbits are more sensitive to heat stress as they have fewer sweat glands and a thicker coat of fur, increasing the heat dissipation complexity. Thus, heat stress hurts rabbits' productivity, meat quality, reproductive performance, antioxidative properties, immune responsiveness, intestinal histomorphology, and microbiome. Nutraceuticals include vitamins, minerals, antioxidants, organic acids, fatty acids, probiotics, prebiotics, synbiotics, enzymes, and medicinal plants due to the possible impacts on maintaining common biological situations, strengthening immune response, and preventing illness, which ultimately led to an increase in productivity. Nutraceuticals have recently attracted a lot of attention to alleviate the adverse impacts of heat stress in rabbit farms. The objective of the current review is to provide acquaintance with the recent findings about the impact of heat stress on rabbit productivity and the advantages of dietary supplementation of nutraceuticals in mitigating it.

Using major genes to mitigate the deleterious effects of heat stress in poultry: an updated review.

Acceleration of global warming has emerged as one of the biggest environmental challenges facing poultry farming. In heat stressed flocks, massive mortality rates and substantial damage to productive performance (eggs and meat) are commonly noticed. Because birds do not have sweat glands, they cannot tolerate high temperatures, especially when combined with high humidity. Under this harsh environmental condition, the birds reduce their feed consumption to decline metabolic energy rate. At an ambient temperature of more than 26°C, the bird increases panting and reduces metabolic rate to get rid of the body's heat increment. There are many scenarios that can be followed to alleviate the adverse effects of heat stress. Management practices, nutritional modification, and/or feed additives are frequently used in poultry farms. However, introducing major genes such as naked neck (Na), frizzle (F), slow feathering (K), and dwarf (dw) could be adopted as a significant solution to improve productive performance in birds raised under high environmental temperatures. The birds carrying these mutations gain popularity owing to their ornamental appearance and highly productive performance at high temperatures. Moreover, utilizing dwarf gene in broiler breeders as a dam line improves adaptability, survivability, and hatchability in flocks kept in hot climates. At hatch, the sex-linked slow feathering mutation has been widely used for wing sexing in some egg-type breeds. The potential use of major genes as a breeding strategy to enhance heat tolerance in chickens has been extensively reviewed.

The potential role of feed restriction on productivity, carcass composition, meat quality, and muscle fibre properties of growing rabbits: A review.

After weaning rabbits, two post-weaning feed restriction (FR) programs are used: a quantitative FR (quantity of feed-limited or time-limited access to feed) or a qualitative FR (modification of diet composition in particularly protein, energy or fibre). Application of post-weaning FR has potential to control post-weaning digestive disorders, and early lower growth rates may be compensated for by later compensatory growth. FR strategies also have potential to enhance feed conversion ratio and reduce carcass fatness. FR may also influence meat chemical composition and physical quality characteristics via controlling the morphological and biochemical properties of muscle fibres. The purpose of this review was to shed light on recent findings regarding benefits of FR on productive performance, carcass characteristics, meat quality characteristics, and muscle fibre properties in growing rabbits.