Effects of thyroid hormone supplementation of canola meal-based diets on growth, and interrenal and thyroid gland physiology of rainbow trout (Salmo gairdneri)

1987 ◽  
Vol 3 (2) ◽  
pp. 73-82 ◽  
Author(s):  
J. F. Leatherland ◽  
J. W. Hilton ◽  
S. J. Slinger
Keyword(s):  
Rainbow Trout ◽  
Thyroid Hormone ◽  
Thyroid Gland ◽  
Salmo Gairdneri ◽  
Canola Meal

Digestibility and Utilization of Canola Meal in Practical-Type Diets for Rainbow Trout (Salmo gairdneri)

1986 ◽  
Vol 43 (6) ◽  
pp. 1149-1155 ◽  
Author(s):  
J. W. Hilton ◽  
S. J. Slinger
Keyword(s):  
Rainbow Trout ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Protein Digestibility ◽  
Salmo Gairdneri ◽  
Canola Meal ◽  
Feed Ingredient ◽  
High Fiber ◽  
Dry Matter Digestibility ◽  
High Level

The digestibility study indicated that dry matter digestibility of canola meal (CM) was low (56.2–60.4%), probably due to the high fiber content of this product and its relatively high level of complex carbohydrates. Energy and protein digestibility of CM were 72.4 and 83.2%, respectively, and the essential amino acid digestibilities were similar to those of protein in the CM. CM cannot successfully replace either soybean meal or fish meal in practical-type diets for young rainbow trout (Salmo gairdneri) without sacrificing growth. Supplementation with additional arginine, lysine and zinc, or energy to CM-based diets did not overcome the growth depressing effects. CM supplementation to the trout diet affected the thyroid gland of the fish, producing a diffuse, microfollicular hyperplasia that increased in severity with increasing CM supplementation. Young rainbow trout appear to be more sensitive to dietary glucosinolates than chinook salmon (Oncorhynchus tshawytscha), and total glucosinolate levels of 158 μg/g or more are deleterious to these fish. We conclude that CM should not, at this time, be included as a feed ingredient in commercial trout diets for young rainbow trout.

Effect of dietary cholecalciferol deficiency on plasma thyroid hormone concentrations in rainbow trout,Salmo gairdneri (Pisces, Salmonidae)

1980 ◽  
Vol 5 (2) ◽  
pp. 167-173 ◽  
Author(s):  
John F. Leatherland ◽  
Brian J. Barnett ◽  
C. Young Cho ◽  
Stanley J. Slinger
Keyword(s):  
Rainbow Trout ◽  
Thyroid Hormone ◽  
Salmo Gairdneri

Effects of starvation and refeeding on plasma T4 and T3 levels and T4 deiodination in rainbow trout, Salmo gairdneri

1983 ◽  
Vol 61 (9) ◽  
pp. 1949-1953 ◽  
Author(s):  
Catherine G. Flood ◽  
J. G. Eales
Keyword(s):  
Rainbow Trout ◽  
Thyroid Hormone ◽  
Salmo Gairdneri ◽  
Diel Variation ◽  
Hormone Levels ◽  
Thyroid Hormone Levels

Plasma T4 (L-thyroxine) and T3 (3,5,3′-triiodo-L-thyronine) levels were decreased by starvation in both terminally sampled and serially sampled rainbow trout held at 11 °C, significant changes in T3 occurring by day 6. Diel variation in plasma T4 was confirmed for fed trout and could explain the previous inability to detect differences in plasma thyroid hormone levels between starved and fed states. Significant elevations in plasma T4 and T3 could be obtained 4 h after feeding previously starved trout. Based on studies with [125I]T4 it is concluded that the food-induced elevation in plasma T3 is due, in part at least, to increased extrathyroidal T4 deiodination to T3.

Canola Meal in Rainbow Trout (Salmo gairdneri) Production Diets

1983 ◽  
Vol 40 (3) ◽  
pp. 281-286 ◽  
Author(s):  
Ronald W. Hardy ◽  
Craig V. Sullivan
Keyword(s):  
Rainbow Trout ◽  
Weight Gain ◽  
Thyroid Function ◽  
Control Diet ◽  
Normal Growth ◽  
Salmo Gairdneri ◽  
Canola Meal ◽  
Future Research ◽  
Food Conversion ◽  
Organoleptic Quality

Production diets containing up to 20% canola meal were fed for 108 d to rainbow trout (Salmo gairdneri) to evaluate the effects on weight gain, food conversion, thyroid function, and organoleptic quality of market-sized fish. Weight gain was not affected by dietary canola meal level. Food conversion values and organoleptic properties were not influenced by dietary treatments. Feed costs were reduced by $18.70 (U.S.) per metric ton compared to control diet at the highest level of dietary canola meal (20%). Thyroid function was significantly affected by dietary canola meal. Dose-related changes in the histological appearance of the thyroid and alterations of plasma thyroxine and 3,5,3′-triiodothyronine levels indicated that compensatory adjustments in thyroid function allowed normal growth to proceed in the canola-fed fish. Possible mechanisms of dietary glucosinolate influence on thyroid function are discussed and areas for future research are suggested.Key words: canola meal, plasma T4, plasma T3, thyroid histology, goitrogen, glucosinolates, trout growth, food conversion, least-cost diets, organoleptic quality

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