| The research object of this paper was grass carp(Ctenopharyngodon idellus),and Sorghum Bicolor(Sorghum hybrid sudangrass)and compound feed were selected as experimental bait,and set up experimental groups with different feeding matching ratios and matching durations of the two,by measuring their growth performance,muscle physical properties and muscle nutritional properties and other indicators,to study the best matching method of the two,and then explore a reasonable and efficient grass carp feeding technology.It provides a real and reliable theoretical basis for the thinking of grass carp rearing in the future.The results of the study are as follows:1.Calculated based on the dry matter ratio of sorghum bicolor and compound feed,the daily feeding amount is based on pasture: compound feed 100:0(G1),75:25(G2),50:50(G3),25:75(G4),0:100(G5),five experimental groups were designed,each with three replicates,and grass carp with an initial body weight of(1283.06±31.61)g was fed for 120 days.The result shows:(1)From the perspective of grass carp growth performance and health level,with the increase of the proportion of compound feed,the weight gain rate,intestinal fat weight,liver body ratio,specific growth rate and serum glucose of grass carp also increased,each test index in G5 group was significantly higher than that in G1 and G2 groups(P<0.05);(2)Judging from the taste of grass carp muscles,the p H value of G1 team was the largest,which was significantly different from other experimental teams(P<0.05).As the proportion of compound feed in feeding increased,the drip loss rate,water loss rate and freezing exudation rate showed an overall trend: gradually increased,the G5 group was significantly different from the G1 and G2 groups(P<0.05);As the proportion of compound feed in feeding increases,the indicators such as hardness,cohesion,shear force also decrease in overall trend,and the recovery force was the opposite.Except for the G4 group in addition,the hardness and shear force of the G5 group were significantly different from those of the other test groups(P<0.05);There was no significant difference in ash content among the experimental groups(P>0.05),the water content decreased with the increase of the feeding ratio of the compound feed,and the crude protein and crude fat was the opposite.As the proportion of compound feed in feeding increased,the diameter of grass carp muscle fibers became larger and larger,and the G1 group was significantly larger than the G4 and G5 groups(P<0.05);(3)From the perspective of grass carp muscle muscle nutrients,the total content of essential amino acids increased with the increase of the proportion of compound feed,and the G1 group was significantly lower than that of the G4 and G5 groups(P<0.05);The content of polyunsaturated fatty acids decreased with the increase of the feeding ratio of compound feed;The highest economic benefit was the G4 group,the input-output ratio of grass carp is 1:1.25,and the net profit of per mu can be around3615.60 yuan.2.Select sorghum bicolor and compound feed as the test bait,and design the whole process of feeding sorghum bicolor team(T1),1/4 course compound feed team(T2),half course compound feed team(T3),The 3/4 course compound feed team(T4)and the whole course compound feed team(T5)were divided into five teams,each with three repetitions,and the grass carp was raised in the pond cage for 120 days.The results showed that:(1)From the perspective of grass carp growth performance and health level,the growth indexes of the fish increased with the increase of the days of feeding the compound feed,and the indexes such as body length,body height,body width,and weight gain rate were significantly different among the experimental teams(P<0.05).Body weight and specific growth rate were the largest in T5 team;The intestinal fat weight of grass carp all increased with the increase of the number of days fed with compound feed,and the indicators in T5 team were significantly higher than those in T1 and T2 teams(P<0.05);(2)Judging from the taste of grass carp muscles,the contents of grass carp albumin and total protein in T4 and T5 teams were significantly lower than those in T1 team(P<0.05);With the increase of the feeding time of compound feed,the indicators such as hardness,elasticity,cohesion,viscosity,chewiness,shear force,and muscle fiber density decrease in the overall trend,while drip loss rate,water loss rate,freezing exudation rate,muscle fiber diameter and restoring force were the opposite.There was no significant difference in muscle stiffness,elasticity and muscle fiber diameter between T4 and T5 teams(P>0.05),but significant differences from T1 and T2 teams(P<0.05);(3)From the perspective of grass carp muscle muscle nutrients,the content of crude protein and crude fat increased with the increase of compound feed feeding time,and the T5 team was significantly higher than the experimental teams except the T4 group(P<0.05);A total of 16 kinds of amino acids were detected in grass carp muscle,and the total content of essential amino acids increased with the increase of feeding time of compound feed;For the total content of the four flavor amino acids,the content of the T5 team was significantly lower than that of the other test teams(P<0.05);The contents of palmitic acid(C16:0)and oleic acid(C18:1)in each experimental team were higher,and the content of saturated fatty acid increased with the increase of compound feed feeding time;The dry matter bait coefficient was 1.90～6.43.With the increase of the feeding time of the compound feed,the dry matter bait coefficient of the feed decreased.When the grass carp was fed to the T1 team,the fresh grass weight required for a weight gain of 500.00 g was 14891.69 g,and the compound feed required for the weight gain of 500.00 g was 1086.72 g when the T5 team was fed the grass carp.In summary,the research results show that feeding grass carp with a certain proportion or a certain length of forage in the breeding cycle of grass carp could not only enhance the water-holding power,hardness and chewiness of grass carp muscles,but also made the muscles more tender and taste better,and it could also improve the health of grass carp,reduce the risk of breeding,and improve the content of umami substances in the muscle,and increase the efficiency of breeding.Therefore,it is recommended to feed grass carp with a ratio of 75%: 25% of compound feed: forage grass every day,or feed compound feed in the first 3/4 of the breeding cycle,and feed grass in the last 1/4 of the cycle.The growth rate and yields can be taken into account at the same time as the quality of the fish. |
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