Immunological and metabolic effects of acute sublethal exposure to glyphosate or glyphosate-based herbicides on juvenile rainbow trout, Oncorhynchus mykiss

Triplicate groups of 15 softwater-acclimated juvenile rainbow trout (Oncorhynchus mykiss) were randomly allocated to one of three treatments: pH 6.5 with no aluminum, pH 5.2 with no aluminum, and pH 5.2 with 30 µg labile aluminum·L-1. The aluminum dose was sublethal and continued for 34 days. Treatment effects on swimming behaviour, metabolism, feeding, food conversion efficiency, and blood parameters were determined. Fish exposed to aluminum displayed hypoactivity that was statistically distinct from both control groups from day 1 onwards. Exposure to acid alone elicited no behavioural effects. There were no significant differences in metabolic rates between the treatment groups. Feeding rates of the fish exposed to aluminum became depressed, reaching a minimum on day 15, and gradually recovered thereafter, but never to the preexposure levels. Swimming behaviour was a more sensitive index of exposure to aluminum than feeding. Fish exposed to aluminum had significantly fewer red blood cells and lower haematocrit than the controls, indicating haemodilution. Aluminum is known to act as a respiratory toxicant, restricting aerobic scope. In addition, these data suggest that fish respond to aluminum exposure by reducing metabolically costly activities such as routine swimming behaviour to allow for the increased maintenance costs associated with acclimation and damage repair.

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Reduction in swimming performance in juvenile rainbow trout (Oncorhynchus mykiss) following sublethal exposure to pyrethroid insecticides

Comparative Biochemistry and Physiology Part C Toxicology & Pharmacology ◽

10.1016/j.cbpc.2013.01.001 ◽

2013 ◽

Vol 157 (3) ◽

pp. 280-286 ◽

Cited By ~ 12

Author(s):

Adam T. Goulding ◽

Lesley K. Shelley ◽

Peter S. Ross ◽

Christopher J. Kennedy

Keyword(s):

Rainbow Trout ◽

Oncorhynchus Mykiss ◽

Swimming Performance ◽

Pyrethroid Insecticides ◽

Juvenile Rainbow Trout ◽

Sublethal Exposure ◽

Rainbow Trout Oncorhynchus Mykiss

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Graded Incorporation of Defatted Yellow Mealworm (Tenebrio molitor) in Rainbow Trout (Oncorhynchus mykiss) Diet Improves Growth Performance and Nutrient Retention

Animals ◽

10.3390/ani9040187 ◽

2019 ◽

Vol 9 (4) ◽

pp. 187 ◽

Cited By ~ 7

Author(s):

Paulo Rema ◽

Subramanian Saravanan ◽

Benjamin Armenjon ◽

Constant Motte ◽

Jorge Dias

Keyword(s):

Body Composition ◽

Rainbow Trout ◽

Oncorhynchus Mykiss ◽

Growth Performance ◽

Tenebrio Molitor ◽

Nutrient Digestibility ◽

Protein Meal ◽

Yellow Mealworm ◽

Juvenile Rainbow Trout ◽

Rainbow Trout Oncorhynchus Mykiss

Insects are emerging as a sustainable alternative to fishmeal and fish oil in aquafeeds. This study assessed the effect of graded incorporation levels of defatted yellow mealworm (Tenebrio molitor) protein meal on juvenile rainbow trout (Oncorhynchus mykiss) growth performance, body composition, and apparent nutrient digestibility. The trial comprised five dietary treatments: control diet with 25% fishmeal, and four experimental diets with yellow mealworm protein meal at 5%, 7.5%, 15%, or 25%, which corresponded to a fishmeal replacement of 20%, 30%, 60%, or 100%, respectively. After 90 days, the graded incorporation of insect protein meal led to a significant stepwise increase in final body weight, and a significant improvement of specific growth rate, feed conversion ratio, and protein efficiency ratio compared to the control treatment. Regardless of the incorporation level, the insect protein meal had no effects on fish whole-body composition and apparent digestibility coefficients of dry matter, protein, fat, phosphorus, and energy. Protein, phosphorus, and energy retention significantly increased in fish fed the diets with an insect protein meal. In conclusion, the yellow mealworm protein meal could effectively replace 100% of fishmeal in the diet of juvenile rainbow trout with positive effects on its overall zootechnical performance.

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Changes in Habitat Use and Feeding Chronology of Juvenile Rainbow Trout (Oncorhynchus mykiss) in Fall and the Onset of Winter in Silver Creek, Idaho

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f93-237 ◽

1993 ◽

Vol 50 (10) ◽

pp. 2119-2128 ◽

Cited By ~ 64

Author(s):

Michael D. Riehle ◽

J. S. Griffith

Keyword(s):

Rainbow Trout ◽

Habitat Use ◽

Oncorhynchus Mykiss ◽

Density Distribution ◽

Stomach Contents ◽

Early Morning ◽

Invertebrate Drift ◽

Juvenile Rainbow Trout ◽

Rainbow Trout Oncorhynchus Mykiss

We assessed changes in density, distribution, and microhabitat of age-0 rainbow trout (Oncorhynchus mykiss) in Silver Creek, a partially spring-fed stream, by periodic snorkeling in August 1987 through January 1988. We examined trout stomach contents and invertebrate drift samples in diel collections in August, September, October, and January to test if the period of feeding shifted from daytime to nighttime, concurrent with a transition to day concealment. In late September, fish aggregated briefly during the day and then began to conceal themselves in macrophyte beds, undercut banks, and submerged sedges and grasses along streambanks as temperature dropped below 8 °C in early October. Fish emerged from concealment at night, and numbers of trout visible were greatest 30–60 min after sunset and about 30 min before sunrise. Periods of peak feeding changed from afternoon and evening in August and September, when fish were day active, to mainly at night in October after the initiation of day concealment. Trout did not feed upon abundant chironomids in the daytime drift in October. In January, fish fed at 1–4 °C on mayflies, and stomachs were fullest in the early morning. Observations suggest that Silver Creek trout experienced a metabolic deficit that began in September.

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