Abstract: The apparent and true amino acid availability values for corn, wheat middlings, rice bran, rice mill feed, soybean meal, peanut meal, cottonseed meal, meat and bone meal, and two different samples of menhaden fish meal were determined in adult channel catfish. Although there was reasonable agreement between protein digestibility values and average amino acid availability values, individual amino acid availabilities were variable within and among the various feed ingredients tested. Therefore, we recommended that amino acid availability values should be used for more accurate catfish feed formulation. In addition, it appears that the use of true amino acid availability values should be used for feed ingredients of relatively low protein content.

Abstract: A series of growth studies, utilizing casein-gelatin based diets supplemented with crystalline amino acids, were conducted to determine the arginine requirement for fingerling channel catfish (Ictalurus punctatus) and to evaluate the effects of excessive levels of dietary lysine and arginine Weight gain and feed efficiency data indicate the arginine requirement to be 103 +/- 007% and 100 +/- 006% of the dry diet, respectively Based on growth this corresponds to 429% of the dietary protein There was no evidence of an arginine-lysine antagonism when excess lysine was fed in diets adequate or marginal in arginine Similarly, growth and feed efficiency data suggest the lack of an antagonism when excess arginine is added to diets marginal in lysine Apparently channel catfish are not as sensitive to disproportionate lysine and arginine levels as are other animals

Abstract: Triploidy was induced in channel catfish (Ictalurus punctatus) by cold-shocking fertilized eggs at 5 C for 1.0 hour starting 5 minutes after fertilization. Chromosome counts from lymphocytes and kidney tissues showed 100% triploidy in the cold-shocked group and 100% diploidy in the controls. Hatching success of eggs cold-shocked 1.0 hour was 79% compared to 89% in the controls. Cold shocks longer than 1.0 hour caused 100% mortality.

Abstract: A feeding experiment conducted in a controlled environment and using a vitamin B12-deficient, but otherwise nutritionally complete, purified diet revealed that intestinal microorganisms in channel catfish synthesized approximately 1.4 ng of vitamin B12 per gram of bodyweight per day. Removal of cobalt from the diet or supplementation with an antibiotic (succinylsulfathiazole) significantly reduced the rate of intestinal synthesis and liver stores of vitamin B12. Radiolabeled vitamin B12 in the blood, liver, kidneys, and spleen of fish fed 60Co in the diet indicated that the intestinally synthesized vitamin was absorbed by the fish. The primary route of absorption was directly from the digestive tract into the blood because coprophagy was prevented in the rearing aquariums and the amount of vitamin B12 dissolved in the aquarium water was too low for gill absorption. Dietary supplementation of vitamin B12 was not necessary for normal growth and erythrocyte formation in channel catfish in a 24-week feeding period. A longer period, however, may have caused a vitamin deficiency since liver-stored vitamin B 12 decreased between the 2nd and 24th weeks.

Abstract: Size comparisons are made between the beaked sea snake, Erhydrina schistosa, and its usual prey, an ariid catfish, Tachysurus maculatus. Of 108 catfish found in as many snake stomachs, most were partially digested. Estimates of catfish length, maximum diameter, and weight were made using linear regression relationships between these measures and index measures determined on entire specimens. Maximum prey diameters were one to two times the neck diameters of the snakes. Prey selection is implicated along both the upper and lower limits of prey size. Large snakes take a disproportionately large number of relatively small fish. This may be a function of prey availability alone. OPTIMAL FORAGJNG THEORIES have encouraged ecologists to look at feeding behavior and habits much more rigorously than in the past. To test theories of selective feeding it is necessary to define and gather data on factors such as foraging time, processing time, net energy gain, feeding frequency, etc. (see Schoener 1971, for a review of optimal foraging theory). Among terrestrial vertebrates snakes are the only major group which specializes in swallowing whole relatively large prey. The prey size of snakes relates directly to prey-handling factors as well as energy considerations. There are numerous reports in the literature on the taxonomic identity of the food of marine snakes (Klawe 1964, McCosker 1975, Voris 1972). The bulk of the data indicates that most species are specialists on some variety of fish. A study of the food and feeding behavior of the beaked sea snake, Enhydrina schistosa, in Malaysia (Voris et al. 1978) revealed behavioral specializations for ingesting spiny catfish (Ariidae). In this paper the relationship between the size and body proportions of E. schistosa relative to its catfish prey is explored. MATERIALS AND METHODS Beaked sea snakes (Enhydrina schistosa) were collected at Muar, Malaysia (2?3'20"N, 102034'20"E). Details of habitat and collection techniques are available elsewhere (Jeffries and Voris 1979). The measurements of snout-vent (s-v) length, girth at the neck, and girth at 3/4 the s-v length were made on snakes relaxed with sodium pentobarbital. The latter two girth measurements represent the minimum and maximum girths respectively for E. schistosa. The neck of E. schistosa is round, and thus girth measurements were converted to diameters by dividing each circumference by -r. All specimens were weighed several months after they had been preserved in formalin and stored in 70 percent ethanol. The stomach contents were removed from the relaxed snakes and preserved in 10 percent formalin. Several months later the fish were transferred to 70 percent ethanol. At Muar the most frequent prey of the beaked sea snakes was the ariid catfish, Tachysurus maculatus (Voris et al. 1978), and this paper deals mainly with this species. Measurements and weights were made on preserved catfish. Body length was measured from the most anterior part of the head to the base of the tail where the fin rays emerged from the body. The maximum diameter, excluding the extended dorsal or pectoral spines, was across the body at the base of the pectoral fins and will be hereafter referred to as the diameter. Tail height was measured as the depth of the caudal peduncle, excluding the fin rays, at the base of the tail. The dorsal fin to tail length was the distance from the posterior junction of the dorsal fin and the body to the base of the tail medio-laterally, where there was a small notch at the base of the tail. E. schistosa swallow catfish head first (Voris et al. 1978), and thus the posterior end of the fish is the last to undergo digestion. Fish lacking some part of the forebody comprised 75 percent of the stomach contents. Of the 108 catfish removed from stomachs, the length, diameter, and weight were measured directly for 27, 16, and 11 specimens respectively. For the remaining partly digested fish, tail height and dorsal fin to tail length measurements were used to estimate the original body dimensions and weight. This was done after first analyzing a series of 50 complete specimens to determine the relationship between the two index measurements (tail height and dorsal fin to tail length) and the length, diameter, and weight of the catfish. A linear relationship exists between tail height and body length, thus the linear regression was used BIOTROPICA 13(1): 15-19 1981 15 This content downloaded from 157.55.39.27 on Mon, 05 Sep 2016 06:03:11 UTC All use subject to http://about.jstor.org/terms TABLE 1. Data on relationships between catfish index measurements (dorsal fin-tail length and tail height in centimeters) and catfish parameters used in comparisons with snakes. Body Maximum Body length diameter weight (log) x n y r n y r n y r Fin-tail 50 1.87x 0.11 1.00 42 0.38x + 0.04 0.99 35 3.29x 1.27 0.99 length Tail height 50 10.03x + 0.91 .99 41 1.97x + 0.27 0.98 34 2.86x + 1.25 0.98

Abstract: Gastrin, pancreatic polypeptide and somatostatin immunoreactive cells in the gut of two fish with stomachs (perch and catfish) and a stomachless fish (carp) were studied by immunocytochemistry. In the gastric mucosa of perch and catfish, cells showing gastrin and somatostatin-like immunoreactivity are found, scattered among the surface mucous cells and mucous neck cells. No pancreatic polypeptide (P.P.) immunoreactive cells are detected in the gastric mucosa. Cells showing gastrin and P.P.-like immunoreactivity are observed in the intestinal mucosa of perch, catfish and carp. In this location no somatostatin immunoreactive cells are found.

Abstract: One hundred and eighty-seven each of channel catfish, Ictalurus punctatus, blue catfish, Ictalurus furcatus, and their reciprocal hybrid crosses were stocked communally in a 0.1-hectare pond (7,480 fish/hectare) in April 1977. Each group was heat-branded prior to stocking for subsequent identification. The fish were grown for 181 days, after which the pond was fished for 35 man-hours (350 man-hours/hectare) on October 16 and 17. The pond was drained on October 19 and the remaining fish were harvested. A total of 290 kg (518 fish) was harvested by fishing and draining. Seventy-five (14.5%) of the fish were caught by the anglers in the two days. The hybrids were more susceptible to angling than the parent species. Heterosis for catchability was 158.6% by number and 203.6% by weight of fish caught. Channel catfish ♀ x blue catfish ♂ hybrids were more catchable than the reciprocal hybrids. Average length of all fish that were caught was greater than for those that were not caught. Fishing success in ...

Abstract: Cell lines from apparently normal gill, gonad, and kidney tissue of adult walking catfish (Clarias batrachus) were established and have been subcultured 75, 80, and 95 times, respectively. The cell...

Abstract: Two wild and two domestic strains of channel catfish Ictalurus punctatus demonstrated different spawning periods among strains. This character may be under genetic control. Egg hatchability was variable and did not differ significantly among strains or strain crosses. Deformed fry occurred in all spawns, but (with one exception) their frequency did not differ significantly among strains or crosses, and may have been due to environmental factors. Female broodfish weight was positively correlated with total weight and number of eggs of the spawn, but negatively correlated with average egg weight. Egg size was not correlated with hatchability or percent deformed fry.

Abstract: Specimens of Clarias gariepinus (Burchell, 1822), collected seasonally from eight dams and the Olifants River in Lebowa, South Africa, were regularly infested with Paracamallanus cyathopharynx and Procamallanus laeviconchus as well as larval Contracaecum spp. This is the first record of Paracamallanus cyathopharynx and of Procamallanus laeviconchus from Clariidae in South Africa.

Abstract: Intraperitoneal immunization of channel catfish, Ictalurus punctatus , with Salmonella paratyphi in Freund's complete adjuvant produced persistent agglutinating antibody titers of hundreds of thousands during a 1-year response. Bactericidal activity of 2 high-titered sera averaged 30% and 20%. Post-immunization bactericidal activity varied little and remained within 10% of pre-immunization bactericidal activity. Fresh channel catfish serum from unimmunized catfish exhibited 100% bactericidal activity against S. paratyphi . Lysozyme was present in fresh channel catfish serum at 1.8 μ/ml serum or 34 ng lysozyme/mg protein.

Abstract: Blue catfish (Ictalurus furcatus), channel catfish (I. punctatus), white catfish (I. catus), and four of their hybrids were evaluated for winter growth in two experiments. The genetic groups of channel catfish were the geographic races from Auburn, Kansas, Marion, and Rio Grande, and intraspecific hybrids, Marion x Kansas and Auburn x Rio Grande. Interspecific (females listed first) hybrids were channel x blue, blue x channel, channel x white, and white x blue. All populations were subdivided into selected lots and random lots. Selected groups consisted of the largest 10% of the population at 18 months. The catfish were fed 0.5 to 2.0% of their body weight, 3 to 6 days a week, depending on water temperature. Growth of white catfish was faster (P = 0.05) than that of all other groups. Among channel catfish, those from more northerly geographic locations performed best. The outstanding growth potential of the white catfish was not transmitted to the channel x white and white x blue hybrids. Blue ca...

Abstract: SUMMARY Juvenile African catfish Clarias gariepinus between 100 and 200 mm total length from Lake McIlwaine, Zimbabwe are able to digest plant proteins. The digestibility of three major plant proteins (maize, sunflower seed and soya meal) was 30,0, 65,4 and 84,3% respectively. C. gariepinus excreted between 27 and 55% of its soluble nitrogen as urea. Fats from one diet were found to spare proteins and to be 73% utilized. The basal metabolic rate of juvenile catfish may be represented by the general formula: BM = 2,56 - 0,40 (In W) - 0,10 (In W) (FS) where BM is the basal metabolic rate in cal g−1 h−1, W is the mass in grams and FS is the feeding state (expressed as zero for a feeding fish and one for a fasting fish). The metabolism of starving, fasting, feeding, and stressed active juvenile fish was found to be approximately 0,28, 0,56, 1,23 and 4,5 cal. g_1 h_1 respectively. World protein shortages and the contribution that fish culture can make are discussed. Sample calculations show catfish lose up to ...

Abstract: Channel catfish Ictalurus punctatus subjected to a diet deficient in vitamin C for 150 days showed a decrease in backbone collagen and hydroxyproline concentrations, whereas the mineral: Collagen ratio and bone density increased. These changes resulted in a 20% reduction in bone strength and a 46% increase in vertebral elasticity. The backbone of channel catfish exposed to the insecticide toxaphene for 90 days also had decreased collagen, but hydroxyproline concentration, mineral: Collagen ratio, and bone density all increased. These alterations in backbone composition resulted in a 34% increase in strength and a 39% decrease in vertebral elasticity. In both experiments, hydroxyproline concentrations in backbone collagen had the greatest influence on the structural properties of vertebrae, whereas collagen, calcium, and phosphorus concentrations did not. Mechanical properties seemed to be more sensitive indicators of vertebral structural integrity than did biochemical ones or bone density.

Abstract: Alkaline phosphatase and peroxidase activities were investigated in typical neutrophils and in vacuolated cells, the latter considered to be another type of neutrophil in catfish blood. This study was carried out by light- and electron-microscopy. Two lines of neutrophils were recognized in the peripheral blood of catfish. Alkaline phosphatase activity was present only in the vacuolated neutrophils; peroxidase activity appeared only in the typical neutrophils. The presence of two types of neutrophil in catfish blood suggests that important steps of neutrophil evolution occurred in fish.

Abstract: Food intake, growth, conversion efficiency and body composition of the non-air breathing catfish Mystus vittatus (Bloch) were studied in relation to different feeding levels. Fish weighing 817.9 ± 104.00 mg was found to consume a maximum of 156.0 mg live Tubifex worm/g day-1. Geometrically derived feeding rates of 6.75, 23.00 and 26.00 mg dry food/g live fish day-1 represent the maintenance, optimum and maximum levels respectively. The SDA increased from 6.75 mg/g day-1 at maintenance to 13.50 mg/g day-1 at maximum feeding rate. Starvation brougt about increase in body water content, while there was concomitant decrease in fat and crude protein.

Abstract: Although anitmicrobial drugs are frequently added to water to treat bacterial diseases of fish, their absorption is largely unquantified. Channel catfish weighing 3–5 g each were exposed to varying concentrations (4 mg/L to 32 mg/L) of chloramphenicol, erythromycin, furpyrinol, and oxytetracycline, respectively. Antibiotic levels measured after 5 h utilizing Bacillus subtilus spore germination inhibition showed that furpyrinol and oxytetracycline were absorbed by the fish in proportion to the antimicrobial concentration in the water. Minimum inhibitory concentrations can be attained in the fish with practical concentrations of these drugs in the water. Erythromycin (carrier-free) was poorly absorbed and chloramphenicol was not absorbed. Significant antibiotic degradation in water occurred in all drugs except furpyrinol.Key words: fish, antimicrobic, chloramphenicol, erythromycin, furance, oxytetracycline

Abstract: Melanochromis crabro sp. nov., a member of the "Mbuna" group, is described from Lake Malawi. It feeds upon a variety of foods, but appears to be adapted to feed on Argulus africanus, a branchiuran parasite commonly found on the catfish, Bagrus meridionalis. It is suggested that the host-cleaner association also facilitates an egg-stealing habit, since M. crabro robs B. meridionalis of its eggs which are laid on the substratum.