Study of the Nutritional Regulatory Function and Anti-Stress Capability of Cottonseed Meal Protein Hydrolysate in Crucain Carp (Carassius Auratus Gibelio)
|School||Nanjing Agricultural College|
|Course||Animal Nutrition and Feed Science|
|Keywords||cottonseed meal hydrolysate nutritional regulation heat stress HPLC crucian carp (Carassius auratus gibelio)|
This study was focused on the nutritional regulatory function and anti-heat stress ability of cottonseed meal protein hydrolysate (CMH) on crucian carp. It would provide theoretical basis for using cottonseed meal protein hydrolysate replace of fish meal and developing modern style aquatic systems.An experiment was carried out to evaluate the effects of different dietary levels of CMH on the growth, digestibility, body composition and serum biochemical indices on crucian carps. A total of240Fish (mean initial weight13±0.5g)(mean±S.D) were devided into four groups and fed diets containing0,10,50and100g/kg of CMH (CMH0,1,5and10, respectively) for9weeks. At the end of the experiment, the weight growth ratio (WGR) of crucian carps was significantly higher in fish fed CMH5(147.18%) than in fish fed CMH0(133.46%) and CMH10(130.02%)(P<0.05), and the lowest feed conversion ratio (FCR) was observed in CMH5(1.73)(P<0.05). The apparent digestibility (AD) of crude protein (CP) and crude lipid was significantly higher in CMH1and CMH5than in CMH0and CMH10(P<0.05). For the whole body composition, there were no significant differences in crude lipid and ash among all treatments (P>0.05). However, CP content was significantly higher in CMH5than in CMH0and CMH10(P<0.05). In addition, the highest value (P<0.05) of zinc (Zn) content in muscle was observed in CMH5, and the iron (Fe) content was higher in fish fed CMH5and CMH10than in fish fed CMH0and CMH1. However, there were no significant differences in muscle manganese (Mn), magnesium (Mg) and copper (Cu) among all treatments (P>0.05). Furthermore, the addition of5%CMH significantly reduced serum superoxide dismutase (SOD) activities, glucose (GLU) levels and cortisol concentrations, and fish fed CMH5showed the highest insulin-like growth factor-1(IGF-I) level among all treatments (P<0.05).The present study was conducted to evaluate the effects of cottonseed meal hydrolysate (CMH) on the stress response to high temperature of crucian carp and whether different dietary levels of CMH could influence fish welfare. Fish (mean initial weight3± 0.5g)(mean±S.D) were fed diets containing0,10,50and100g/kg of CMH (CMH0,1,5and10, respectively) at27℃. After feeding for63days, fish were exposed to34℃water for1hour, and the respiratory rate of fish in each tank was recorded. The levels of cortisol, glucose, enzyme activities (Superoxide Dismutase, Acetylcholinesterase, and Glutamic-oxaloacetic Transaminase) in serum were measured as parameters of tolerance to high temperature stress. After heat stress, the fish fed CMH5showed the highest SOD activities compared to that of0mg CMH group (P<0.05), but other CMH supplemented groups did not show any significant differences on the SOD activities from CMH0. Significantly (P<0.05) lower GOT activities were observed in fish fed CMH5and CMH10compared to fish fed CMH0. High temperature induced the increasing respiratory rate (RR) of fish, although severity of this negative effect was not the same for all groups. The lowest RR, serum cortisol and glucose were found in fish fed CMH5(P<0.05), however, there were no significant differences between CMH5and CMH10. In conclusion, increased dietary levels of CMH would enhance stress resistance and welfare to high temperature stress in crucian carps.The study was designed to investigate relationship between the intestinal small peptides in cottonseed meal protein hydrolysate and the peptides in blood circulation of crucian carp. Five groups of crucain carp were infused into the front intestine with saline (control), cottonseed meal (CM), cottonseed meal protein hydrolysate (CMH), fish meal (FM) and casein (CA) solution (1ml·100g-1weight). Blood was collected after20min infusion from tail vein. The results of analyses by HPLC showed that the total amount of protein, peptides and free amino acid in plasma of crucian carp in all treatments were higher than that of fish in control group. Furthermore, the total amount of protein, peptides and free amino acid in fish fed CMH was almost20times higher than that of fish fed CM. Besides, the plasma small peptides in fish fed CMH was higher than other groups and increased respectively28.02%,22.90%,8.19%and10.14(molecular weight:120Da-1800Da). The results showed that the increase of peptides in plasma was closely related with the kind and amount of peptides in intestine. The study showed that the small peptides which were absorbed into blood circulation in fish fed CMH were much higher than fish fed other treatments.