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H. A. Poston

Publications and source records attributed to H. A. Poston.

At least 19 recordsLinked to original sources
USGS1991

Effects of dietary aluminum on growth and composition of young Atlantic salmon

A 16‐week feeding experiment was conducted to measure the effects of supplemental dietary aluminum (0, 25, 50, 100, 500, 1,000, 1,500, and 2,000 mg/kg diet) on growth, survival, feed conversion, and proximate composition of Atlantic salmon ( Salmo salar ), mean weight 4.8 g. No significant differences ( P > 0.05) in growth, survival, or feed conversion were found among fish fed the different levels of aluminum. Body fat increased significantly in fish fed aluminum at the rate of 2,000 mg/kg of diet. Total ash was significantly lower in fish fed 1,000–2,000 mg aluminum/kg of diet than in those fed smaller amounts. Differences in concentration of individually measured minerals (aluminum, copper, iron, manganese, and magnesium) were not significant in either carcass or vertebrae of experimental fish. Supplemental dietary aluminum (up to 2,000 mg/ kg of diet) had no measurable beneficial or obvious adverse effect on fingerling Atlantic salmon.

Progressive Fish-Culturist↗
USGS1991

Response of rainbow trout to soy lecithin, choline and autoclaved isolated soy protein

Fry of rainbow trout ( Oncorhynchus mykiss ) were fed, from first feeding (mean weight, 0.12 g), basal diets containing either a nonautoclaved (raw) sodium proteinate form of isolated soy protein (ISP) or the same ISP autoclaved at 0.56 kg/cm 2 and l 10°C for 30 min. In the three‐way factorial, 16‐week study, I measured the effects of autoclaving ISP on the growth, survival, and chemical composition of rainbow trout at three levels of soy lecithin (0, 4, and 8%) and two levels of choline (0 and 0.3%). Fish fed raw ISP grew no faster with or without choline than did those fed the basal diet, but those fed heated ISP with choline showed a quantitatively small but significant advantage in weight gain. Whereas fish fed 4% lecithin with raw ISP more than tripled weight gain compared with fish fed the basal diets, fish fed 4% lecithin with heated ISP grew seven times as fast as those fed no lecithin or choline. Rainbow trout fed choline and 4% lecithin with heated ISP (but not raw ISP) grew significantly faster than those fed heated ISP and 4% lecithin alone. The higher level (8%) of lecithin promoted no more growth than the 4% lecithin with either raw or heated ISP. Among rainbow trout fed heated ISP, 4 and 8% supplemental lecithin – either with or without choline – reduced mortality to the same level, but 8% lecithin was the only concentration that significantly reduced the mortality of fish fed raw ISP. The results of calorimetry and determination of nitrogen with larger (235–375 g) rainbow trout individually held in metabolism chambers indicated that autoclaved ISP enhanced the growth and survival responses offish to lecithin by increasing digestible protein and energy and metabolizable energy. This higher amount of bioavailable energy and protein increased the deposition of body fat.

Progressive Fish-Culturist↗
USGS1991

Influence of feeding rate on performance of Atlantic salmon fry in an ozonated water reuse system

A 4‐week trial was conducted to determine the optimal feeding level in percent body weight of a commercially prepared, practical diet for early feeding fry of Atlantic salmon ( Salmo salar ) in an ozonated water reuse system at 17–18°C. Triplicate groups of swimup (0.19‐g) fry were fed one of seven levels of Biodiet starter diet calculated for hatchery constants of 2.5, 3.5, 4.5, 5.5, 6.5, 7.5, and 8.5. Feeding levels (percent body weight) were derived at the start of the study and again at 2 weeks by dividing mean body length, in inches, into the respective hatchery constant. Mean body weight and body fat content increased significantly with each increment in level of feeding through a hatchery constant of 6.5. after which there was no further increase. Body protein decreased as feeding increased through hatchery constant 6.5; ash content decreased through hatchery constant 5.5. Results indicated that young Atlantic salmon fed at low feeding rates (2.47–5.44% body weight) in the water reuse system were underfed, but fish fed at 5.46–8.41% body weight grew at a favorable rate.

Progressive Fish-Culturist↗
USGS1991

Choline requirement of swim-up rainbow trout fry

Triplicate 150‐fish lots of first‐feeding fry of rainbow trout ( Oncorhynchus mykiss ; initial mean weight, 0. 12 g) were fed casein–gelatin‐based diets containing 0, 200, 400, 800, 1,000, 2,000, 4,000, or 8,000 mg choline/kg of feed for 12 weeks to determine their need for dietary choline. Although the growth rates of fry were suboptimal, results showed that fry needed no more than 4,000 mg choline/kg casein–gelatin diet for maximum growth and 2,000 mg/kg for maximum body fat and minimum protein. Survival was significantly lower for fish fed 800 mg choline/kg of diet than for those fed greater amounts of the nutrient. These results suggest that the dietary choline requirement of early feeding salmonids is greater than that previously reported for older salmonids. The amount of choline needed by fishes apparently decreases with age or size.

Progressive Fish-Culturist↗
USGS1991

Response of Atlantic salmon fry to feed-grade lecithin and choline

First‐feeding Atlantic salmon ( Salmo salar ) were fed different levels (0, 2, 4, 6, and 8% of diet) of feed‐grade lecithin with and without 0.3% supplemental choline in a diet containing a sodium proteinate form of autoclaved isolated soybean protein. After 14 weeks at 9.2°C, Atlantic salmon fed 6% lecithin with or without added choline had gained the most weight. Fish fed supplemental choline without lecithin gained significantly more weight ( P ≤ 0.05) than did fish fed the basal diet, but choline did not increase weight gain at any level of lecithin. Feed conversion (weight fed/weight gain) improved with increasing lecithin up to 4% and improved even more for fish fed 6% lecithin and 0.3% choline. Only 4% lecithin with or without choline was needed to yield the highest concentration of body fat, but carcass dry matter was highest and ash and protein were lowest in fry fed 8% lecithin alone or 6% lecithin and 0.3% choline. Neither lecithin nor choline influenced mortality, which was low in all groups. Results indicate that 6% dietary feed‐grade lecithin promotes maximum weight gain by swim‐up Atlantic salmon fry fed autoclaved isolated soybean protein as the primary protein.

Progressive Fish-Culturist↗
USGS1990

Effects of ozonated-water reuse on salinity tolerance of Atlantic salmon

We conducted several seasonal aquarium experiments to determine survival and body chemistry changes of Atlantic salmon ( Salmo salar ) after 24‐h exposures to salinities of 0, 16.5, 33, and 40‰ at 10°C. Fish transferred directly to test aquaria from an ozonated, 100‰ closed water‐reuse system at 18°C were compared with fish acclimated to single‐use water at 10°C for 1–3 weeks before salinity challenges in solutions of sea salt. In the initial (December and January) challenges, all Atlantic salmon from the closed system with a fork length of at least 200 mm survived exposure to 16.5 and 33‰ salinity, but not 40‰; fish 135 mm long or shorter did not survive exposure to 33‰ salinity. In later experiments, prior acclimation of fish to single‐use water at 10°C helped protect them against exposure to high salinity (i.e., 33 and 40‰) at 10°C. Few fish that were moved directly from the water‐reuse system into test aquaria lived for 24 h in 33 or 40‰ salinity. Atlantic salmon contained less water at 33‰ than at 16.5‰ or in fresh water, but carcass water content did not differ within salinity treatments between fish previously held at 18°C and those acclimated to 10°C and single‐use water. At each salinity, serum sodium concentration tended to rise less in those fish acclimated to the singleuse system than in those transferred directly from the reuse system to the aquaria. The exposure of Atlantic salmon to an elevated acclimation temperature (18°C) in the water‐reuse system exacerbated the disruption of their ionic exchange at exposures to 33 and 40‰ sea salt. A trace of copper (27 μg/L) in the reused water also may have reduced the salinity tolerance of these fish.

Progressive Fish-Culturist↗
USGS1990

Performance of rainbow trout fry fed supplemental soy lecithin and choline

Three feeding experiments were conducted with early‐feeding fry of rainbow trout ( Oncorhynchus mykiss ; initial mean weight, 0.10–0.12 g) to determine their need for lecithin contained in soy lecithin (SL), with and without supplemental choline. The source of assay protein was an isoelectric form (RP 100) of isolated soy protein (ISP) in experiment 1, a sodium protein ISP (RP 101) in experiment 2, and an ether‐extracted herring meal in expenment 3. Duration of the feeding trials was 20 weeks for experiment 1 and 16 weeks for experiments 2 and 3. Analysis of variance showed that supplemental SL and choline each increased body weight gain, survival, and body fat, and improved feed conversion (amount fed/weight gain). The extent of beneficial effects varied with type of diet fed. Fish fed either of the ISPs needed at least 4% supplemental SL, either with or without 0.3% choline, for highest survival, but survival of all fish fed extracted herring meal was high. Although choline alone enhanced growth, at least 4% SL, either with or without choline, was necessary for maximum growth.

Progressive Fish-Culturist↗
USGS1988

Interrelations of oxygen concentrations, fish density, and performance of Atlantic salmon in an ozonated water reuse system

In a 16‐week study, we stocked duplicate groups of 3.3‐g Atlantic salmon ( Salmo salar ) in 25‐fish increments (25 to 100 fish/6.5‐L jar) and in 250‐fish increments (250 to 1,000 fish/144‐L trough), in an ozonated, 100% closed water reuse system, to examine changes in fish performance in response to rearing at different densities and loadings within the system. Maximum rearing density (kg!m 3 ) reached 219 in jars and 125 in troughs. Maximum loading (ratio of fish weight to water flow) reached 0.45 kg/(L/min) in jars, and 0.79 kg/(L/min) in troughs. A rise in water temperature from 18.9 to 21°C during weeks 11 and 12 was accompanied by a drop in effluent dissolved oxygen (DO), followed by an increase in mortality and a decline in biweekly weight gain. Later declines in water temperature to 18.4°C, and reductions in biomass, were followed by reduced mortality and increased weight gain. In both jars and troughs, mortality increased when dissolved oxygen dropped to 6.5 mg/L or lower, water temperature reached 19.6°C, and biomass reached 50–75 kg/m 3 , or 0.1–0.2 kg/(L/min) flow. Changes in DO, weight gain, and mortality per unit change in density (kg biomass/m 3 ), were lower in jars than in troughs, but changes in these responses in terms of flow (kg/[L/min]) were lower in troughs. Results of this study suggest that, for optimum growth, survival, and feed conversion of Atlantic salmon in an ozonated water reuse system, dissolved oxygen should be at least 6.5 mg/L. Maintenance of an acceptable level of oxygen should minimize detrimental effects offish density or elevated water temperature.

Progressive Fish-Culturist↗
USGS1986

Response of rainbow trout to source and level of supplemental dietary methionine

1. Methionine and total sulfur amino acid (TSAA) requirements of rainbow trout ( Salmo gairdneri ) were investigated by feeding graded isosulfurous levels of l - and dl -methionine, l -cystine, and the free acid and calcium forms of methionine hydroxy analog (MHA). 2. Added cystine did not promote growth, survival or prevent cataracts. 3. l -methionine produced fastest growth, followed by dl -methionine, CaMHA and free acid MHA. 4. Trout fed CaMHA gained 85.7 and 92.3% as much as those fed l -methionine and dl -methionine. 5. Within each experiment, the level of L-methionine isomer that prevented cataracts was constant (1.86 g/100g protein in experiment (1), 1.45 in experiment (2) and was lower than for maximum growth (2.89 and 2.15 g) regardless of methionine source.

Comparative Biochemistry and Physiology, Part A: P↗
USGS1983

Factors affecting dietary requirement and deficiency signs of L-tryptophan in rainbow trout

Two experiments were conducted to determine the concentration of dietary tryptophan needed for optimal growth and survival of fingerling rainbow trout ( Salmo gairdneri ), to characterize signs of tryptophan deficiency, and to ascertain the effects of niacin on deficiency signs. Test diets containing either hydrolyzed or intact casein were fed with graded levels of added L-tryptophan (0.0, 0.25, 0.50, 0.75 and 1.0 g/100 g protein). Maximum growth occurred at 0.75 and 0.50 g tryptophan in fish fed hydrolyzed and intact casein, respectively. Changes in mineral and amino acid mixtures in the intact casein diet yielded a cation-anion (Na + K - Cl) balance of + 15.3 meq/100 g diet and pH of 6.44, compared with a balance of -21.3 and -25 meq, and pH 5.8 and 4.4 for unmodified hydrolyzed and intact casein diets, respectively. Analysis of growth by the polynomial regression function; Y = 0.16 + 0.429 X - 0.26 X 2 , where Y = mean daily gain in grams, and X = grams of added tryptophan/100 g protein, predicted that at least 0.58 g of tryptophan was needed for maximum weight gain. Analysis of apparent pathology-free fish by the function; Y = 34.33 + 147.33 X = 83.87 X 2 , where Y = percentage with no signs of deficiency, and X = grams of added tryptophan, predicted that 0.63 g tryptophan/100 g protein was needed for optimum health scores. Deletion of supplemental niacin did not affect fish response to tryptophan.

Journal of Nutrition↗
USGS1982

Biological effects of dietary T-2 toxin on rainbow trout, Salmo gairdneri

A 16-wk feeding study was conducted to evaluate the chronic toxicity of graded levels (0, 1.0, 2.5.5, 10 and 15 mg/kg of chemically pure dietary T-2 toxin (4,15-diacetoxy-8-(3-methylbutyryloxy)-12,13-epoxy-Δ 9 -tricothecen-3-ol) in 1-g rainbow trout, Salmo gairdneri , held in 9°C single-passage well water. Levels of T-2 toxin > 2.5 mg/kg depressed growth, efficiency of feed use, hematocrit, blood hemoglobin concentration and feed acceptance, and caused a transitory edema in a dose-dependent manner. Growth of trout fed a semipurified diet containing the toxin was described by the function: Y = 0.265 + 142.075 e (0.029 X 1 − 1.554x 2 3.7 ), where Y = gain as percentage starting weight per wk; X 1 is time in wk and 0 ⩽ X 1 ⩽16; and X 2 is T-2 content of diet in mg/kgand 0⩽ X 2 ⩽15. Exposure of fish to T-2 toxin did not affect activity of intestinal lumen chymoirypsin or trypsin, nitrogen digestibility or metabolizabte energy. Feeding of 15 mg/kg T-2 toxin to adult trout caused hemorrhaging in the intestines and regurgitation of subsequently intubated feed regardless of T-2 loxin content.

Aquatic Toxicology↗