The Nutritional Response Of Gifu Tilapia To The Addition Of Phosphorus In Practical Feed

This research,Gift tilapia(Oreochromis niloticus)as the research object and monocalcium phosphate,calcium hydrophosphate,MDCP as the research materials,was conducted to study the effects of the dietary phosphorus levels and the source of phosphorus on growth,physiology and biochemistry indexes,body composition and apparent digestibility of feed conventional components.The feeding trial has two texts:experimentl studied on the demand of phosphorus in practical feed for Gift tilapia,while experiment2 studied on nutritional responses of Tilapia on three kinds of different inorganic in the practical feed.Experiment 1:The text was designed to add monocalcium phosphate to make seven groups of forage whose final monocalcium phosphate concentration were 0.0%?0.5%?1.0%?1.5%?2.0%?2.5%?3.0%respectively.525 tilapia(initial weight 24.40±0.15g)were randomly divided into 7 groups with 3 replicates in each group and 25 fish per replicate.Every ration group were raising in the 1.2m×0.5m×0.35m glass aquarium and the feeding rate was 3%-5%.The experimental period lasted for 56days.The results showed that:1)?There were significant effects on specific growth rate(SGR),feed conversion rate(FCR),deposition rate of dry matter,protein deposit rate(PDR),ash deposition rate with the addition of monocalcium phosphate in the feed(P<0.05),however when the level of monocalcium phosphate was below 1.0%,there was no significant effects on fat deposit rate(P>0.05);?There were no significant effects on condition factor and body length/body height,while significant effect on the viscera index;?Moisture and the content of protein of tilapia were not sensitive to the change of the level of monocalcium phosphate,but sensitive to the fat of fish,ash,the content of P;?With the increase of the level of phosphorous,digestibility of dry matter,protein,ash,P trend to upgraded earlier and fell latter;?The supplementation of monocalcium phosphate in the feed has significant effects on the activity of AKP,SOD,GOT and GPT;With the rise of ration MCP,the activity of AKP increased,while the others trended to upgraded earlier and fell latter;?The supplementation of monocalcium phosphate in the feed has significant effects on the activity of MDH,PK,lipoprotein lipase,hepatic lipase and the content of the liver malondialdehyde(P<0.05),with increasing phosphorus levels,these enzymes are on the rise,but rising trend after the malondialdehyde content was reduced,at the 15G.kg-1 level is reached the lowest values.??All landowners feed calcium dihydrogen phosphate is added to reduce the crude fat content of tilapia organizations along with the increase of the adding level organizations appeared a downward trend in fat and liver crude fat content decreased;Through microscopic observation of the liver tissue paraffin section,found that in the control group tilapia fat cells in the liver tissue than experimental group increased obviously.Experiment2,This test Gift tilapia as the research object,study three kinds of calcium and phosphorus calcium dihydrogen phosphate(MCP),dicalcium phosphate(DCP),MDCP in dietary total phosphorus concentration of 1.28%Gift tilapia growth performance,body index,whole fish conventional nutritional composition,biochemical indices of serum and liver and apparent digestibility of feed,in order to determine the most suitable inorganic phosphorus Gift tilapia species,in order to reduce phosphorus emissions and pollution of the environment,reduce feed costs,improve breeding efficiency.Add to imports of Peruvian fish meal,soybean meal,rapeseed meal and cottonseed meal as a protein source on the basis of 2.0%MCP,2.3%DCP,2.0%MDCP by microcrystalline cellulose leveling made total phosphorus content of 1.28%of the experimental diets.Each group feed 3 parallel,each parallel to the 25 initial weight 29.4± 0.15 g of Gift tilapia,indoor 1.2m × 0.5m × 0.35m glass tank 8 weeks to study the different dietary phosphorus Gift tilapia growth,body index,serum biochemical parameters,feed apparent digestibility and whole fish,intestine,muscle,and liver fat content.The results show that?There were significant effects on weight gain,feed conversion ratio with different inorganic phosphorus source of Gift tilapia(P<0.05),MCP group and DCP group weight gain rate than the MDCP group increased by 14.4%,13.6%,MCP group and DCP groups feed coefficient lower than MDCP group,6.0%,5.1%,respectively.?There were no significant effects on relative fatness and body/body high with different inorganic phosphorus source of Gift tilapia(P>0.05);?There were no significant effects on whole body nutrient composition with different inorganic phosphorus source of Gift tilapia;while MCP group the content of liver,muscle,intestine fat were significantly lower than MDCP group(P<0.05),there were no significant effects on the content of muscle,intestine fat with DCP group and MDCP group(P>0.05);?There were significant effects on Gift tilapia serum glutamic oxalacetic transaminase,alkaline phosphatase and superoxide dismutase,the MCP group was the highest,lowest MDCP group,DCP group centered;? There were significant effects on Apparent digestibility of phosphorus with different inorganic phosphorus source of tilapia,the MCP group was the highest,lowest MDCP group,DCP group centered;In summary,the following conclusions:1 Optimum Dietary phosphorus added levels can significantly improve tilapia weight gain rate,specific growth rate,lower feed conversion ratio.2 Optimum Dietary phosphorus added levels improve tilapia alkaline phosphatase activity,improve feed digestibility and nutrient deposition efficiency.3 Suitable phosphorus added levels can be improved tilapia antioxidant capacity.4 Suitable phosphorus added levels can reduce the number of fat cells in the liver tissue and reduce the fat content of the fish.5 The most suitable phosphorus concentration for practical feed of Tilapia is 1.19%and the optimal added level of MCP is 1.58%.6 The best source of phosphorus in practical feed of Tilapia is MCP,followed by DCP,MDCP is the worst.