Pros and Cons of Dietary Vitamin A and Its Precursors in Poultry Health and Production: A Comprehensive Review

Abstract

Vitamin A is a fat-soluble vitamin that cannot be synthesized in the body and must be obtained through diet. Despite being one of the earliest vitamins identified, a complete range of biological actions is still unknown. Carotenoids are a category of roughly 600 chemicals that are structurally related to vitamin A. Vitamin A can be present in the body in the form of retinol, retinal, and retinoic acid. Vitamins are required in minute amounts, yet they are critical for health, maintenance, and performing key biological functions in the body, such as growth, embryo development, epithelial cell differentiation, and immune function. Vitamin A deficiency induces a variety of problems, including lack of appetite, decreased development and immunity, and susceptibility to many diseases. Dietary preformed vitamin A, provitamin A, and several classes of carotenoids can be used to meet vitamin A requirements. The aim of this review is to compile the available scientific literature regarding the sources and important functions, such as growth, immunity, antioxidant, and other biological activities of vitamin A in poultry.

Effects of supplemental vitamin A on reproduction and antioxidative status of aged laying hens, and growth, blood indices and immunity of their offspring

“…In this way, VA is crucial for maintaining bird fertility ( Yaripour et al, 2018 ). Similarly, Khan et al (2023) reported that VA supplementation in poultry supports growth, feed efficiency, egg production, quality, immunity, hatchability, and congenital malformations.…”

“…Fat-soluble vitamins, including VA, are a micronutrient necessary for immune system upkeep, embryonic growth, epithelial tissue integrity, and reproduction in chickens ( Yuan et al, 2014 ; Chen et al, 2016 ; Khan et al, 2023 ). The embryonic development of birds is positively impacted by the VA stored in the liver and egg yolk ( O'Byrne and Blaner, 2013 ; Ebeid et al, 2023 ).…”

Nutritional Balance Matters: Assessing the Ramifications of Vitamin A Deficiency on Poultry Health and Productivity

“…The essential role of vitamin A in poultry vision stems from its multiple important functions [2]. One of its primary roles is to support and maintain overall eye [75].…”

“…Among the many essential micronutrients, vitamins play a crucial role in supporting vital physiological functions. Understanding the significance of vitamins, particularly vitamin A (retinol), in poultry health and productivity is paramount for optimizing poultry management practices [2,3].…”

“…Exclusively animal-derived feeds such as fish liver oil and fish meal are the primary sources of vitamin A. However, there are certain plant pigments called carotenoids (e.g., βcarotene) that have the potential to exhibit vitamin A activity via metabolic conversion [2,6]. It is important to note that only a small portion of the carotenoids found in nature can be converted into vitamin A by mammals and birds [7].…”