Tilapia fish guts provide insight to growth hormone effects

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By Milthon Lujan

USA – One of the several ways that growth hormone (GH) relates to the growth physiology of teleost fishes (a large group of ray-finned fishes such as tilapia) is that it helps them absorb nutrients.

In a new study from the University of Hawai?i at Manoa’s College of Tropical Agriculture and Human Resources Department of Human Nutrition, Food and Animal Sciences, alumni Cody Petro-Sakuma and Jason Breves, Research Specialist Fritzie Celino-Brady and Associate Researcher Andre Seale investigated the effects of GH on the gene expression of nutrient transporters in Mozambique tilapia (Oreochromis mossambicus). The paper appeared in the journal General and Comparative Endocrinology.

The researchers surgically removed the tilapia’s pituitary gland and gave it hormone replacement. Their goal was to assess whether GH directs the gene expression of molecular targets involved in nutrient transport, such as the GH receptor, peptide transporters, an amino acid transporter, glucose transporters and others. The researchers also checked where the effects of GH on the gene expression of these targets showed up in the intestine.

The tilapia without the pituitary showed diminished expression of most of the genes tested, and GH replacement was effective at restoring the expression of GH receptor, the peptide transporters and one of the glucose transporters. The authors’ findings indicate that “GH supports growth, at least in part, by stimulating the gene expression of its cognate receptor and key nutrient transporters in the intestine.” The authors further conclude that the identification of such GH targets may contribute to the development of strategies for enhancing the growth of domesticated fishes.

“Using the tilapia as a model species, the paper shows that the growth-promoting effects of growth hormone also occur via the stimulation of specific nutrient transporters in the intestine,” explained Seale. “Ultimately, beyond furthering our understanding on how growth and metabolism is regulated, there is great interest in improving efficiency in aquaculture, which includes improving nutrient utilization, increasing growth, and reducing feed, operation costs and time to market.”

Petro-Sakuma C, Celino-Brady FT, Breves JP, Seale AP. Growth hormone regulates intestinal gene expression of nutrient transporters in tilapia (Oreochromis mossambicus). Gen Comp Endocrinol. 2020;292:113464. doi:10.1016/j.ygcen.2020.113464 

Source: UH News

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