We had a program at the PB conv (Fish nutrition)0n this topic. It is metabolism (bioenergetics theory). I will add some threads.
http://forums.pondboss.com/ubbthreads.ph...true#Post126584 Bioenergetic models estimated that the largemouth bass population in these ponds consumed between 132 and 171 kg ha (roughly 150 lbs per acre) of bluegills in the first 300 days after stocking to maintain the observed growth.
Each population of largemouth bass was predicted to have consumed 4.2 to 6.7 times their own biomass in bluegills in 300 days to maintain these growth rates and biomass.
Recent research has revealed consumption-dependent error in many bioenergetic models, including the one used in this study, which was particularly large when growth rates were fast . Thus, the percent of maximum consumption by largemouth bass estimated in this study were likely underestimated which probably indicates that the bluegill densities in the ponds used in this study may not be great enough to meet predator demand in the future, leading to slower growth, poorer condition, and a possibly lower production of trophy-sized fish.
A little confusion on the BG size. The catch rate BG were 5 inch average while the stock size (150% of normal in the study or the recommended 2000 at the convention) were small BG as were the LMB when stocked.
In this study LMB numbers were low and survival to age 1 was below normal. Even at those reduced rates the LMB were most likely to have over eaten the BG forage base which was 150% of normal if the study would have gone beyond 1 year.
http://forums.pondboss.com/ubbthreads.ph...true#Post175828 http://forums.pondboss.com/ubbthreads.ph...true#Post259185North American Journal of Aquaculture
Volume 65, Issue 2, 2003
Evaluation of Practical Bluegill Diets with Varying Protein and Energy Level
DOI:
10.1577/1548-8454(2003)65<147:EOPBDW>2.0.CO;2
Richard H. Hoagland IIIa, D. Allen Davisa, Nguyen Anh Tuana & William J. McGrawa
pages 147-150
No problems related to water quality or disease were encountered during the experiment. As indicated by their high survival (>98%), the fish were able to tolerate repeated handling and weighing. The performance of the fish under laboratory conditions is summarized in Table 2. Fish maintained on a diet containing 44% protein and 8% lipid (designated as D44/8; other diets designated analogously) exhibited significantly higher final weight (12.99 versus 9.3610.70 g) and weight gain (643.9% versus 429.7507.3%) than fish maintained on diets containing lower levels of protein. Fish given D44/8 also had significantly higher feed efficiency (77.9%) than those on diets with lower levels of protein (60.666.7%). Total feed offered was significantly higher for fish maintained on D44/8 (14.4 g) and D44/12 (14.2 g) than for those on D32/10 (12.6 g) and D32/6 (12.5 g), with the remaining diets being intermediate. No significant differences or notable trends in the protein conversion efficiency values among fish given the various diets were found. Proximate analyses for dry matter, protein, and lipid in whole-body samples were similar among all but one of the treatments. The single exception was the proportion of dry matter in fish maintained on D32/10, which was higher than that in fish from all other treatments.
From Fish Nutrition
The immense variety of cultured finfish species hampers efforts to simplify production industry wide. Approximately 170 taxa are currently cultured, including carnivores, herbivores, planktivores, and omnivores, each posing its own set of nutritional demands .
Fish meal has proven to be an excellent dietary protein source for finfish, leading to its description as an ideal protein. The ideal protein concept is based on the premise that if the amino acid profile of the feed mimics the whole-body amino acid profile of the animal being fed, protein utilization and growth should be maximized
Lipids, fatty acids, and their derivatives play a role in virtually every physiological process that occurs and for this reason dietary lipid composition and content represent a massive sector of overall nutrition. Nowhere is this more true than in finfish nutrition where lipid can exceed protein in the body composition of finfish, a testament to the physiological and energetic importance of this nutrient class (Tocher2003). Aside from physiological importance, lipids are indispensable energy sources, especially for finfish, which are not well-adapted to carbohydrate utilization.
Dietary protein and energy must be kept in proper balance because a deficiency or excess of dietary energy can reduce growth rates. Fish fed diets deficient in energy will metabolize more expensive dietary protein to meet energy requirements. Excess dietary energy can decrease protein intake and suppress growth.
finfish do not require carbohydrates in their diet,
complex carbohydrates cannot be digested and utilized efficiently by most finfish species. A general dichotomy exists in the carbohydrate digestive ability of warmwater omnivores and herbivores versus the inability of coolwater and coldwater carnivores, which lack the appropriate function necessary for digestion of carbohydrates.
For this reason, diets fed to these fish rarely contain more than 20% complex carbohydrate
Conversely, warmwater omnivores or herbivores (e.g., channel catfish, tilapia, common carp, and white sturgeon) adapt well to diets containing as much as 40% dietary carbohydrate .
Although vitamins and minerals are required in minute amounts compared with protein, lipid, and so forth, they are critically important,
Every micronutrient has a deficiency disease associated with it, the effects of which are sometimes irreversible or fatal. For a few vitamins and most minerals, excess can be equally detrimental, resulting in toxicity.
Because fish growth often is limited by food availability, supplemental feeding is a logical tool to improve the condition of fish in small impoundments as the energy cost for bluegill to feed on pellets is small relative to the high caloric intake, which can be 4-5 times greater than those fed natural foods (Schalles and Wissing 1976).
Substantial increases in the standing stock of bluegill in ponds that receive pellet feed have been recorded (Schmittou 1969) and, in lakes, pellet feeding has been found to increase the number of large bluegills (Nail and Powell 1975).
These results indicate that total fish production and production of bluegill were each increased approximately 75 to 80% by supplemental feeding in 19 months after stocking (Schmittou 1967)
Previous studies demonstrated that feed in excess of 10 pounds per acre per day in bluegill ponds was not utilized. Some accumulated and decomposed, thus depleting the supply of dissolved oxygen which resulted in fish kills (Schmittou 1967) .
the rate of growth of sunfish can be increased by short-circuiting the food cycle, thereby producing harvestable size sunfish in a shorter period of time than would occur under natural conditions (Carnes 1966).
The pellet size should be approximately 20-30% of the size of the fish species mouth gape. Feeding too small a pellet results in inefficient feeding because more energy is used in finding and eating more pellets. Conversely, pellets that are too large will depress feeding and, in the extreme, cause choking. Select the largest sized feed the fish will actively eat.
Addition of supplemental pelleted feed did not contribute to the rate of growth of young shad, but did increase the growth and spawning frequency of adults.
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