Wendy M. Sealey

Evaluation of the Ability of Partially Autolyzed Yeast and Grobiotic-A to Improve Disease Resistance in Rainbow Trout

Abstract We evaluated the ability of partially autolyzed yeast and Grobiotic-A to improve immune response and disease resistance in rainbow trout Oncorhynchus mykiss. Experimental diets were prepared by adding partially autolyzed yeast or Grobiotic-A to a practical trout diet at the manufacturer-recommended level of 2%; the control was the same diet without supplementation. Rainbow trout (initial weight = approximately 14.3 g) were cultured in 145-L fiberglass tanks (50 fish/tank; 3 tanks/diet) in a freshwater flow-through system. Fish were hand-fed the diets to apparent satiation 3 times/d, 6 d/week for 9 weeks. At 3 and 9 weeks postweighing, fish were sampled to determine respiratory burst activity, plasma protein, total immunoglobulin and lysozyme, and tumor necrosis factor-alpha (TNF-α) expression. At the conclusion of the feeding trial (9 weeks), fish remaining after sampling were pooled by diet; one subsample was examined for the ability to respond humorally to infectious hematopoietic necrosis viru...

Report of the Plant Products in Aquafeed Strategic Planning Workshop: An Integrated, Interdisciplinary Research Roadmap for Increasing Utilization of Plant Feedstuffs in Diets for Carnivorous Fish

This article was downloaded by: [Bellis, Diane]On: 24 November 2008Access details: Access Details: [subscription number 905736162]Publisher Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,37-41 Mortimer Street, London W1T 3JH, UK

Dietary Supplementation of Vitamin C and/or Vitamin E before or after Experimental Infection with Streptococcus iniae Has Limited Effects on Survival of Hybrid Striped Bass

Abstract To examine the prophylactic and therapeutic value of dietary vitamins C and/or E given in megadoses against disease, juvenile reciprocal-cross hybrid striped bass (female white bass Morone chrysops × male striped bass M. saxatilis) were fed experimental diets with 2,500 mg vitamin C/kg diet (100× the established dietary requirement), 300 mg vitamin E/kg (10× the dietary requirement), or both at the requirement or megadose levels for 3 or 6 weeks before and 0, 3, or 7 d after experimental exposure to Streptococcus iniae. The first dead fish was observed 3 d following intraperitoneal injection with S. iniae, and mortality did not appear to be significantly affected by dietary vitamin level or length of feeding. Infection with S. iniae reduced tissue total ascorbate and α-tocopherol levels at 14 and 21 d postinjection relative to those in uninfected control fish. Dietary vitamin E at 300 mg/kg significantly increased mortality when fed for 3 weeks before exposure. Additionally, dietary vitamin C at ...

Evaluation of Protein Reduction and Lysine Supplementation of Production Diets for Channel Catfish

Abstract A 2-year continuous production trial was conducted in earthen ponds to evaluate lysine supplementation of practical diets as a means of reducing the need for total dietary protein and limiting the nitrogenous waste production of channel catfish Ictalurus punctatus. Fingerling channel catfish with an initial weight of 34.1 g were stocked in twelve 0.04-ha ponds in early summer at a density of 24,710 fish/ha. The experimental diets consisted of three practical diets containing 30% crude protein (control), 25% crude protein, or 25% crude protein supplemented with 0.5% lysine·HCl to provide the same level of lysine as the control diet. Each diet was fed to fish in four replicate ponds to apparent satiation once a day when water temperature was greater than 15°C. Ponds were top-harvested three times during the study with a 4.1-cm-mesh grader seine to remove marketable fish. The yields of marketable fish at each harvest period were not significantly (P > 0.05) affected by diet. Following each harvest, ...

Prebiotic supplementation has only minimal effects on growth efficiency, intestinal health and disease resistance of Westslope cutthroat trout Oncorhynchus clarkii lewisi fed 30% soybean meal

Prebiotics have successfully been used to prevent infectious diseases in aquaculture and there is an increasing amount of literature that suggests that these products can also improve alternative protein utilization and digestion. Therefore, the objective of this study was to examine whether prebiotic supplementation increased the growth efficiency, intestinal health, and disease resistance of cutthroat trout fed a high level of dietary soybean meal. To achieve this objective, juvenile Westslope cutthroat trout (Oncorhynchus clarkii lewisi) were fed a practical type formulation with 0 or 30% dietary soybean meal with or without the commercial prebiotic (Grobiotic-A) prior to experimental exposure to Flavobacterium psychrophilum. Juvenile Westslope cutthroat trout (initial weight 7.8 g/fish ±SD of 0.5 g) were stocked at 30 fish/tank in 75 L tanks with six replicate tanks per diet and fed their respective diets for 20 weeks. Final weights of Westslope cutthroat trout were affected by neither dietary soybean meal inclusion level (P = 0.9582) nor prebiotic inclusion (P = 0.9348) and no interaction was observed (P = 0.1242). Feed conversion ratios were similarly not affected by soybean meal level (P = 0.4895), prebiotic inclusion (P = 0.3258) or their interaction (P = 0.1478). Histological examination of the distal intestine of Westslope cutthroat trout demonstrated increases in inflammation due to both increased soybean meal inclusion level (P = 0.0038) and prebiotic inclusion (P = 0.0327) without significant interaction (P = 0.3370). Feeding dietary soybean meal level at 30% increased mortality of F. psychrophilum cohabitation challenged Westslope cutthroat trout (P = 0.0345) while prebiotic inclusion tended to decrease mortality (P = 0.0671). These results indicate that subclinical alterations in intestinal inflammation levels due to high dietary inclusion levels of soybean meal could predispose Westslope cutthroat trout to F. psychrophilum infection.

Dietary Protein Source and Level Affects Growth in Neon Tetras

Abstract Nutritional studies for aquarium fishes like the neon tetra Paracheirodon innesi are sparse in comparison with those for food fish. To determine the optimum dietary protein level and source for growth of neon tetras, diets were formulated to contain 25, 35, 45, and 55% dietary protein from either marine animal protein or plant protein sources in a 4 × 2 factorial treatment design. Neon tetras (initial weight, approximately 0.12 g) were reared in 5-L fiberglass tanks (25 fish/tank, 3 tanks/diet) in a freshwater recirculating system. Fish were hand-fed the experimental diets three times per day for 12 weeks. Average weight gain of neon tetras fed diets with marine protein sources was significantly higher than that for fish fed diets based on plant proteins. Fish fed diets containing 45% or 55% crude protein had significantly greater weight gain than did fish fed 25% crude protein from either protein source. Fish fed 25% crude protein from either source had a significantly higher feed conversion rat...

Preliminary Investigation of Dietary Soy Sensitivity in Shovelnose Sturgeon

Sturgeon culture has developed greatly since the 1980s. Cultured sturgeon are often fed a commercial salmonid feed high in fish meal (FM). However, economic and sustainability concerns have put pressure on aquafeed manufactures to incorporate alternative proteins such as soybean meal (SBM). This experiment investigates dietary SBM sensitivity in shovelnose sturgeon (Scaphirhynchus platorhynchus). Diets were formulated to contain 0%, 17%, 34%, and 51% SBM and fed for 8 weeks. Weight gain, specific growth rate (SGR), feed efficiency (FE), body and liver composition, and intestinal histology were determined. Although sturgeon growth rates were low for all diets, weight gain in fish fed the diet with 17% SBM averaged 55.6% of sturgeon fed the fish meal-based control diets. Statistically lower negative growth and FE (P < 0.05) were observed when SBM was included at 51% of the diet. However, whole-body proximate composition and hepatic lipid and glycogen content were not altered by dietary SBM inclusion level, and histological evaluation of the distal intestine was inconclusive. These results provide preliminary insight into the effect of diets containing high levels of SBM on growth and health of Scaphirhynchus sturgeon.

Feed Characteristics Alter Growth Efficiency of Cutthroat Trout

Abstract Hatchery-cultured cutthroat trout Oncorhynchus clarkii fed some commercially available rainbow trout feeds display slow growth and increased mortality. Feed characteristics such as buoyancy and texture alter feed acceptance in some fish species, but their effects have not been adequately addressed in cutthroat trout. Therefore, the objective of this study was to examine whether feed structure and behavior preferences explain the decreased hatchery performance of juvenile cutthroat trout. To achieve this, we conducted two feeding trials in which we fed Westslope cutthroat trout O. clarkii lewisi and Snake River finespotted cutthroat trout O. clarkii behnkei a single diet formulation manufactured to display four different characteristics (floating, sinking, semimoist pellets, or a flake feed) and compared consumption, weight gain, and survival. In the first feeding trial, we stocked Westslope cutthroat trout (initial weight 11.3 g ± 0.5 g) at 20 fish/tank. We used two different sizes of tanks, with...

Water system is a controlling variable modulating bacterial diversity of gastrointestinal tract and performance in rainbow trout

A two-phase feeding study evaluating performance of rainbow trout and comparing luminal and mucosal gastrointestinal tract (GIT) bacterial community compositions when fed two alternative protein diets in two rearing systems was conducted. Alternative protein diets (animal protein and plant protein diets) balanced with crystalline amino acids: lysine, methionine and threonine or unbalanced, were fed to rainbow trout in two separate water systems (recirculating (RR) and flow-through (FF)) for a period of 16 weeks. The four diets, each contained 38% digestible protein and 20% fats, were fed to rainbow trout with an average weight of 12.02 ± 0.61 g, and sorted at 30 fish/tank and 12 tanks per dietary treatment. Phase 1 lasted for 8 weeks after which fish from each tank were randomly divided, with one-half moved to new tanks of the opposing system (i.e. from RR to FF and vice versa). The remaining halves were retained in their initial tank and system, and fed their original diets for another 8 weeks (phase 2). After the 16th week, 3 fish/tank were sampled for each of proximate analysis, body indexes and 16S rRNA analysis of GIT microbiota. Fish weight (P = 0.0008, P = 0.0030, P<0.0010) and body fat (P = 0.0008, P = 0.0041, P = 0.0177) were significantly affected by diet, diet quality (balanced or unbalanced) and system, respectively. Feed intake (P = 0.0008) and body energy (P<0.0010) were altered by system. Body indexes were not affected by dietary treatment and water systems. Compositional dissimilarities existed between samples from the rearing water and GIT locations (ANOSIM: (R = 0.29, P = 0.0010), PERMANOVA: R = 0.39, P = 0.0010), but not in dietary samples (ANOSIM: R = 0.004, P = 0.3140, PERMANOVA: R = 0.008, P = 0.4540). Bacteria were predominantly from the phyla Proteobacteria, Firmicutes and Bacteroidetes. Their abundance differed with more dissimilarity in the luminal samples (ANOSIM: R = 0.40, P = 0.0010, PERMANOVA: R = 0.56, P = 0.0010) than those from the mucosal intestine (ANOSIM: R = 0.37, P = 0.0010, PERMANOVA: R = 0.41, P = 0.0010). Bacteria generally associated with carbohydrate and certain amino acids metabolism were observed in the mucosal intestine while rearing water appeared to serve as the main route of colonization of Aeromonas and Acinetobacter in the rainbow trout.