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Embryonic development of common wolffish (Anarhichas lupus L.) was studied at constant temperatures 5.0, 7.0, 9.0, 11.0, 13.0 and 15.0°C. Duration of development from egg activation to several morphological stages including 50% hatching was determined. At 5.0–11.0°C, the survival rate of eggs to hatching ranged from 51 to 88% with a tendency to increase at 5.0 and 7.0°C. Morphological anomalies, bacterial contamination and large mortalities were observed in eggs incubated at 13.0 and 15.0°C. The period of hatching lasted from 10 to 50 d in different egg groups. Embryo length and yolk sac volume at identical morphological stages of development showed only slight relation to temperature. At lower temperatures newly hatched larvae were longer and at more advanced stages of ontogeny. Normal numbers of fin rays in larvae (mean values 74 for dorsal fin and 46 for anal fin) were observed at 5.0 and 7.0°C and in most larvae at 9.0°C. At 11.0 and 13.0°C, many rays were absent, with mean values for dorsal fin 60 and 39 respectively and for anal fin 28 and 4 respectively. The approximate upper limit for normal development of fin rays appeared to be 9.0 °C. 相似文献
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Peculiarities of reproduction, early ontogeny, methods of egg incubation, and influence of temperature on development are compared in wolffish (Anarhichas lupus L.) and in salmonids, mainly Atlantic salmon (Salmo salar L.). Reproductive indices of females are similar in both species, but differ in males due to the small production of sperm in wolffish, a difference explained by internal fertilization in the latter species. The rate of embryonal development until the beginning of differentiation of fin fold at the same temperature is similar in both species, but the period from activation to hatching is more than twice as long in wolffish as in Atlantic salmon. Wolffish hatch at a more advanced stage with a small remnant of yolk sac and begin to feed shortly thereafter. As in Atlantic salmon, eggs and larvae of wolffish have a wide range of temperature resistance except before and after hatching. Based on the difference of life cycles in wolffish and salmon, technologies for their artificial breeding are compared. 相似文献
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D A Pavlov 《Aquaculture Research》1995,26(3):195-205
Larvae of the common wolffish. Anarhichas lupus L., hatched from artificially inseminated eggs incubated in the laboratory, were reared on live foods at temperatures ranging from 2 to 10oC. Temperatures over 8oC were too high for newly hatched larvae, but after rearing for 17 days at an average temperature of 6.5oC, the young could tolerate 11oC. The maximum growth rate was observed in the process of keeping of fish during the first 5 months of growing at a temperature gradually increasing up to 14oC. At an age of 577days the average weight of the young in two size groups was 160 and 248 g. A stocking density or five fish 1?1 is satisfactory for young at weight less than 0.2 g. Subsequent growth during 2 months at density of 3-4 fish 1?1 was delayed, compared with that at density of one fish1?1, and all fish reared at high density were infected by Trichodina sp. The growth rate in captivity is compared with that in nature. 相似文献
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Rosas-Ballina M Olofsson PS Ochani M Valdés-Ferrer SI Levine YA Reardon C Tusche MW Pavlov VA Andersson U Chavan S Mak TW Tracey KJ 《Science (New York, N.Y.)》2011,334(6052):98-101
Neural circuits regulate cytokine production to prevent potentially damaging inflammation. A prototypical vagus nerve circuit, the inflammatory reflex, inhibits tumor necrosis factor-α production in spleen by a mechanism requiring acetylcholine signaling through the α7 nicotinic acetylcholine receptor expressed on cytokine-producing macrophages. Nerve fibers in spleen lack the enzymatic machinery necessary for acetylcholine production; therefore, how does this neural circuit terminate in cholinergic signaling? We identified an acetylcholine-producing, memory phenotype T cell population in mice that is integral to the inflammatory reflex. These acetylcholine-producing T cells are required for inhibition of cytokine production by vagus nerve stimulation. Thus, action potentials originating in the vagus nerve regulate T cells, which in turn produce the neurotransmitter, acetylcholine, required to control innate immune responses. 相似文献
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