Effects of dietary thyroid hormones on the red drum (Sciaenops ocellatus)

Abstract

Four separate 8-week feeding trials were conducted to assess the effects of supplementing semipurified diets with either triiodothyronine (T3) or thyroxine (T4) at 0, 2, 10, and 50 mg/kg on growth and body composition of juvenile red drum (Sciaenops ocellatus) held in artificial brackish water (6‰) and artificial seawater (32‰). At both levels of salinity, increasing doses of T3 resulted in fish with reduced weight gain, feed efficiency, condition factor (weight × 100/length(3)), and muscle ratio (muscle weight × 100/body weight), as well as a lighter body color. Significant (p < 0.05) effects of T3 on the proximate composition of whole body, liver, and muscle were variable, generally reflecting decreased lipid and protein storage in liver and muscle, respectively. The two highest doses of T3 given to seawater adapted fish increased survival. Dietary T4 supplementation had no distinctive effects on appearance, growth or proximate body composition. These results indicate that whereas T3 may function to regulate protein and lipid metabolism in red drum, dietary supplementation with T3 leads to a hyperthyroidism-induced catabolic state. The elevated endogenous thyroid hormone levels found in fish fed optimal diets may thus adequately supply tissue needs during juvenile growth.

Effect of oral administration of l-thyroxine (T4) on growth performance, digestibility, and nutrient retention in Channa punctatus (Bloch) and Heteropneustes fossilis (Bloch)

“…Moon et al (1994) also did not observe any effect of T 4 in red drum. According to Lam (1973) the use of excessive doses of thyroid hormones results either in growth inhibition or in excessive mortality.…”

Stimulatory effect of thyroid hormones improves larval development and reproductive performance in alligator gar (Atractosteus spatula) and spotted gar (Lepisosteus oculatus)

“…The absence of anabolic effect on other fast‐growing warm water species has already been reported (Moon et al . ). Moreover, Mendoza et al .…”

“…Although, the dose of hormone and the method of administration may be critical factors influencing results (Moon et al 1994;Power et al 2001).…”

“…In contrast, little information is available on the effects of TH on warm water, fastgrowing species. Such fish may be expected to exhibit characteristics of thyroid function different from salmonids due to differences in temperature optima, nutrient requirements, or salinity tolerance (Moon et al 1994). In addition, the paucity of data on thyroid physiology in ancient fish (Youson 2007) makes further description of the role of TH in lepisosteid larval development especially important, and may provide alternatives to improve larval robustness and survival.…”

Short‐term physiological role of thyroxine administration on plasma metabolites and growth performance of Sterlet sturgeon Acipenser ruthenus

“…Some reported that TH can stimulate synthesis of fatty acid (FA) and cholesterol (CHOL) in various species (Blennemann, Leahy, Kim, & Freake, 1995;Hapon, Varas, Gimenez, & Jahn, 2007;Plisetskaya, Woo, & Murat, 1983;Varghese & Oommen, 1999), but others found that TH caused lipolysis (for instance FA and CHOL degradation) and decreased lipid deposition (Kremser et al, 1991;Ness & Lopez, 1995;Sheridan, 1986Sheridan, , 1994. Moreover, while some studies reported that survival and growth of some species can be enhanced by TH administration (Blanton & Specker, 2007;Brown, Urbinati, Zhang, Brown, & McComb-Kobza, 2014;Navarrete-Ramírez et al, 2011), others found no effects (Moav & McKeon, 1992;Yamano, 2005), or even toxic (inhibitory) effects on survival or growth (Abrahams & Pratt, 2000;Moon, MacKenzie, & Gatlin, 1994;Rousseau, Le Belle, Marchelidon, & Dufour, 1999;Sharma & Patiño, 2013). Some of these conflicting observations may be due to methodological differences among studies but are also likely that the actions of TH on metabolism and growth are complex and vary from species to species in certain respects.…”