Seasonal changes in the reproductive condition and body composition of free-ranging red drum, Scianops ocellatus.

Abstract Ž . Ž . Adult red drum Sciaenops ocellatus from a wild, autumn fall spawning population were studied over a 1-year period to evaluate seasonal changes in body composition in comparison with cultured red drum. Each month, female and male fish were captured and blood sampled. Standard Ž . length and weight were measured, and gonads, liver, intraperitoneal fat IPF , and a sample of Ž . muscle tissue were collected from each fish. Gonadosomatic index GSI , hepatosomatic index Ž . HSI , IPF ratio, protein and lipid composition of muscle and liver tissues, and lipid class composition of liver samples were determined for each fish. All tissue indices exhibited a similar Ž . seasonal cycle in both sexes, with highest HSI in spring March-April and maximal IPF ratio in May, followed in September and October by minimal values for HSI and IPF ratio. Whereas GSI was low, gonadal histology demonstrated activation of spermatogenesis and oocyte development in July and August. Liver composition varied dramatically throughout the year. Liver lipid content Ž . ranged from 7.4% of wet weight in November to 30.2% in August, with triglycerides TG being the most abundant component at all times. Liver protein was more stable, ranging from 11.5% in August to 16.3% in September. Muscle composition was relatively constant, with muscle crude protein ranging from 20.5% to 25.6% of wet weight and muscle lipid ranging from 0.4% to 2.2% R. Craig et al.r Aquaculture 190 2000 89-102 90 of wet weight. These data indicate that red drum utilize the liver as a major depot for lipid. Depletion of maximal lipid reserves from liver and IPF in late summer indicates that lipid stored during active spring and summer feeding supplies energy for reproduction which is mobilized Ž . rapidly within 1 month in this fall-spawning species. Body composition of wild fish is similar to that of laboratory cultured red drum.

A SWOT Analysis of the Use of Marine, Grain, Terrestrial-Animal and Novel Protein Ingredients in Aquaculture Feeds

A variety of new feed ingredients are emerging in the aquaculture feed sector. While the technology readiness of these options varies across and within the new ingredient classes, it remains important to consider them in terms of the overall feed ingredient spectrum. In this review, the use of marine, grain, terrestrial animal by-product and a range of novel (e.g., bacterial and yeast) resources being considered as potential protein feedstuffs for use in aquafeeds is explored. In comparing the nutritional attributes of each of the ingredient classes, an assessment framework is applied based on understanding the critical knowledge required to be able to accommodate any ingredient in a formulation process. To further examine each of the different ingredient classes a Strength-Weakness-Opportunity-and-Threats (SWOT) analysis is applied, to enable some consideration of what future potential may exist across the spectrum and what risks and opportunities they may bring. It is noted that all ingredients have strengths and weaknesses, and that there is no such thing as the perfect ingredient. By better appreciating the positives and negatives of each ingredient, it becomes possible to increase adaptability in responding to the various opportunities for their use in feeds

A SWOT Analysis of the Use of Marine, Grain, Terrestrial-Animal and Novel Protein Ingredients in Aquaculture Feeds

A variety of new feed ingredients are emerging in the aquaculture feed sector. While the technology readiness of these options varies across and within the new ingredient classes, it remains important to consider them in terms of the overall feed ingredient spectrum. In this review, the use of marine, grain, terrestrial animal by-product and a range of novel (e.g., bacterial and yeast) resources being considered as potential protein feedstuffs for use in aquafeeds is explored. In comparing the nutritional attributes of each of the ingredient classes, an assessment framework is applied based on understanding the critical knowledge required to be able to accommodate any ingredient in a formulation process. To further examine each of the different ingredient classes a Strength-Weakness-Opportunity-and-Threats (SWOT) analysis is applied, to enable some consideration of what future potential may exist across the spectrum and what risks and opportunities they may bring. It is noted that all ingredients have strengths and weaknesses, and that there is no such thing as the perfect ingredient. By better appreciating the positives and negatives of each ingredient, it becomes possible to increase adaptability in responding to the various opportunities for their use in feeds

Genetic effects on tolerance to acute cold stress in red drum, Sciaenops ocellatus L

Abstract Genetic e¡ects on cold-stress tolerance were assessed for red drum (Sciaenops ocellatus), an economically important sciaenid ¢sh in the southern USA. Thirty¢ve families were generated via 'natural'spawning of multiple sets of ¢ve breeders (three dams  two sires) in individual brood tanks. O¡spring from the 35 families were transferred abruptly from an acclimation temperature of $24 1C to 5.7 1C and maintained subsequently at an average temperature of 6.5 1C. O¡spring were assigned a posteriori to individual brood¢sh (dam and sire) based on genotypes at nuclear-encoded microsatellites. Heritability of the survival^time probability function was estimated using a proportional hazard approach and an animaladditive model. The estimated heritability was 0.20 (95% CI: 0.07^0.40), indicating a signi¢cant genetic component to acute cold-stress tolerance in red drum

Growth and physiological effects of replacing fishmeal with dry-extruded seafood processing waste blended with plant protein feedstuffs in diets for red drum (Sciaenops ocellatus L.)

The utilization of seafood processing waste (SPW) is a potential means of reducing aquaculture’s reliance on marine forage fish. Therefore, in an effort to recycle valuable nutrients such as high-quality proteins and polyunsaturated fatty acids from potentially wasted seafood processing, a novel approach was evaluated to enrich plant-derived feedstuffs. Four thermally-processed blends were manufactured by dry-extruding a mixture of either soybean meal (SBM) or distillers dried grains with solubles (DDGS) with two different ratios of SPW (60:40, and 40:60 of SPW: plant-derived feedstuffs on a wet-weight basis). Five diets were formulated to contain 36 % of crude protein and 12 % of lipid, and each of the four blends comprising treatments (SBM 60:40, SBM 40:60, DDGS 60:40, DDGS 40:60) which contributed 30 % of the dietary crude protein, with SBM providing 45 % and FM providing the remaining 25 %. The reference diet had its protein provided solely by FM. Groups of 30 fish (∼98.8 g/fish) were distributed into 15 fiberglass tanks (1200 L), and fed the experimental diets in triplicate to apparent satiation twice a day for 8 weeks. At the end of the trial, four fish per tank had their intestine samples collected and flash frozen to measure digestive enzymes activities. The remaining fish were pooled per treatment, re-distributed into two tanks per treatment, and fed the experimental diets for an additional week. A transport-induced stress challenge was then performed, and fish were transported in a hauling tank for 2 h. Blood hematocrit, and plasma cortisol, lactate and osmolality, were measured from four fish per treatment at five sampling points: prior to and 30 min after transportation, and at 24, 36 and 48 h after the transport-induced stress challenge. Weight gain was significantly affected by the dietary treatments, with fish fed all blends but the SBM 40:60 outperforming those fed the reference diet. Fish fed all treatments also were significantly different from those fed the reference diet for hepatosomatic index. Dietary treatments also significantly impacted, relative to the reference diet, the activity of trypsin, alkaline phosphatase, and amylase. A lower percentage of red blood cells were observed for fish fed SBM 60:40 when compared to those fed the reference diet, but only before the transport-induced stress challenge. Based on the results of this study, the inclusion of both SPW blends had a favorable influence on production performance of red drum while reducing the fishmeal and fish oil in the diet formulation

The Effect of Aflatoxin-B1 on Red Drum (Sciaenops ocellatus) and Assessment of Dietary Supplementation of NovaSil for the Prevention of Aflatoxicosis

Aflatoxin B1 (AFB1) is a potent carcinogen that causes growth stunting, immunosuppression and liver cancer in multiple species. The recent trend of replacing fishmeal with plant-based proteins in fish feed has amplified the AFB1 exposure risk in farm-raised fish. NovaSil (NS), a calcium montmorillonite clay, has previously been shown to reduce AFB1 bioavailability safely and efficaciously in several mammalian species. This study was designed to: (1) evaluate AFB1 impact on cultured red drum, Sciaenops ocellatus, over the course of seven weeks; and (2) assess NS supplementation as a strategy to prevent aflatoxicosis. Fish were fed diets containing 0, 0.1, 0.25, 0.5, 1, 2, 3, or 5 ppm AFB1. Two additional treatment groups were fed either 5 ppm AFB1 + 1% NS or 5 ppm AFB1 + 2% NS. Aflatoxin B1 negatively impacted red drum weight gain, survival, feed efficiency, serum lysozyme concentration, hepatosomatic index (HSI), whole-body lipid levels, liver histopathological scoring, as well as trypsin inhibition. NovaSil inclusion in AFB1-contaminated diets improved weight gain, feed efficiency, serum lysozyme concentration, muscle somatic index, and intraperitoneal fat ratios compared to AFB1-treated fish. Although not significant, NS reduced AFB1-induced histopathological changes in the liver and decreased Proliferating Cell Nuclear Antigen (PCNA) staining. Importantly, NS supplementation improved overall health of AFB1-exposed red drum

An evaluation of total body electrical conductivity to estimate body composition of largemouth bass,

Measurement of total body electrical conductivity (TOBEC) recently has been used to estimate the body composition of several fish species in a noninvasive manner. The present study was conducted to evaluate the use of TOBEC in estimating body composition of largemouth bass (Micropterus salmoides). A total of 85 largemouth bass weighing 154 to 3245 g were measured for electrical conductivity after which their proximate composition was determined by chemical means. Significant linear relationships existed between the natural logarithm of whole-body ash, lean body mass, lipid, protein, and water content and the natural logarithm of length and/or weight with r2 values ranging from 0.860 to 0.999. Inclusion of the TOBEC value did not significantly improve the prediction accuracy of these models. Equations were developed to allow the prediction of body composition of largemouth bass based on length and weight measurements. Prediction models including only length and weight as variables provided estimates of body components of an independent set of fish that were not significantly different from chemically derived measurements of these components. These models should allow the rapid, nondestructive estimation of body composition of largemouth bass varying in size and condition without the added cost and processing time associated with measurement of TOBEC, although large prediction errors might prevent the detection of ecologically significant differences in body composition. However, with additional data involving narrower fish-size ranges and constant temperatures for the development of prediction equations, TOBEC may improve the prediction accuracy of body composition estimates for largemouth bass