Animal Growth Promotants
نویسنده
چکیده
HISTORICAL DEVELOPMENT In the early 1930s, it was reported that injections of crude pituitary extracts increased growth rates in growing animals and milk production in lactating animals. Subsequent studies led to purification from pituitary extracts of two peptide hormones—prolactin and “growth hormone” or somatotropin—which are important to growth and lactation. Prolactin has many functions ranging from regulation of limb regeneration and salt balance in amphibians to regulation of mammary growth and function in many mammals. It was named prolactin because it was measured (assayed) on the basis of stimulation of mammary growth in rabbits and rodents. Similarly, the term growth hormone arose from the original assay method which was based on growth promotion. When it became evident that “growth hormone” had many actions in addition to growth promotion, its name was changed to somatotropin. The name prolactin has not been changed to better describe its diverse functions.
منابع مشابه
Comparison of alternative beef production systems based on forage finishing or grain-forage diets with or without growth promotants: 1. Feedlot performance, carcass quality, and production costs.
Forty Angus-cross steers were used to evaluate 5 beef cattle management regimens for their effect on growth performance, carcass characteristics, and cost of production. A 98-d growing phase was incorporated using grass silage with or without growth promotants (trenbolone acetate + estradiol implants, and monensin in the feed) or soybean meal. Dietary treatments in the finishing phase were deve...
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Five beef cattle management regimens were evaluated for their effect on meat quality, fatty acid composition, and overall palatability of the longis-simus dorsi (LD) muscle in Angus cross steers. A 98-d growing phase was conducted using grass silage with or without supplementation of growth promotants (Revalor G and Rumensin) or soybean meal. Dietary treatments in the finishing phase were devel...
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The industrialization of livestock production and the widespread use of nontherapeutic antimicrobial growth promotants has intensified the risk for the emergence of new, more virulent, or more resistant microorganisms. These have reduced the effectiveness of several classes of antibiotics for treating infections in humans and livestock. Recent outbreaks of virulent strains of influenza have ari...
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Recent concerns about the use of growth-promoting antibiotics in pig diets have renewed interest in the immunologic and growth-regulating functions of the gastrointestinal (GI) tract. The numerically dense and metabolically active microbiota ofthe pig GI tract represents a key focal point for such questions. The intestinal microbiota is viewed typically as a beneficial entity for the host. Inte...
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تاریخ انتشار 2016