On gastric evacuation characteristics and suitable feeding frequency of <italic>Centropristis striata</italic>

Abstract

The experiments were carried out on juvenile <italic>Centropristis striata</italic>.The gastric evacuation rate(GER) and effects of different feeding frequencies on growth, survival rate, feed coefficient, nutrient composition and enzyme activity were studied. Results showed that when the water temperature was 22 ℃, the wet weight of stomach content decreased significantly in 4 h, then decreased slowly, and finally reached 0.Three mathematical models, including linear model, exponential model and square root model, were used to fit the gastric evacuation rate. The square root model was more suitable for quantitative description of gastric evacuation curve. The equation was <italic>Y</italic>^0.5 = 2.050-0.084<italic>t</italic>.Under water temperature 22-26 ℃, groups of different feeding frequencies were set:F1 (1 time·d^-1), F2 (2 times·d^-1), F3 (3 times·d^-1) and F4 (4 times·d^-1) . After 8 weeks of experiment, the final body weight, weight gain rate, specific growth rate and condition factor increased with the increasing feeding frequency, and there were significant differences between F1 and other groups (<italic>P</italic><0.05). With the increase of feeding frequency, feed coefficient initially decreased and then increased. The feed coefficient of F1 was the highest and that of F2 was the lowest, and there were significant differences between F1 and F2, as well as between F1,F2 and other groups (<italic>P</italic><0.05). With the increase of feeding frequency, water content, ash content, crude protein content, protein efficiency and protein production value of <italic>C</italic>. <italic>striata</italic> decreased, while crude fat showed an increasing trend, and differences among groups were significant (<italic>P</italic><0.05). There were significant differences in serum total protein between F1 and other groups (<italic>P</italic><0.05). There was no significant difference in albumin among groups (<italic>P</italic>>0.05); globulin of F2 was the highest; glucose and triglyceride content increased with the increase of feeding frequency; alanine aminotransferase content and aspartate aminotransferase content increased initially and then decreased with the increase of feeding frequency, and F3 was the highest. Considering the gastric evacuation rate, growth performance, feed coefficient, nutritional components and other indicators, under the experimental conditions, the suitable feeding frequency of juvenile <italic>Centropristis striata</italic> was F2 (2 times·d^-1), which could provide basis and reference for breeding production.