| In this study,the body mass(95.76 ± 7.37 g)Salvelinus malma was used as the research object.The meat content,normal nutrition,mineral element content,amino acid,fatty acid composition and nutritional value of the muscle were first detected and the external morphology of stomach,pyloric caecum and intestinal tract were observed,measured and analyzed respectively,and the digestive enzyme activity of stomach,pyloric blind sac and intestinal tract was measured.To explore the nutritional value and digestive function of Salvelinus malma.The results show that:1.The meat content of Salvelinus malma is 75.63 ± 3.17 %.The back muscle of Salvelinus malma is rich in crude protein(16.46 ± 0.07 %),moderate in crude fat(2.30 ± 0.02 %)and rich in Fe,Zn,P and other mineral elements.The proportion of amino acids is relatively balanced,including 7 kinds of essential amino acids for the human body,the highest content of glutamic acid is 2.40 ± 0.14 %(fresh sample),the limiting amino acids are methionine and valine,and the fresh amino acids account for 6.01 % of the total amino acids.It is rich in various unsaturated fatty acids,mainly linoleic acid(38.10 ± 2.15 %)and oleic acid(24.60 ± 1.20 %),DHA and EPA contents are 7.21 ± 0.01 % and 1.75 ± 0.12 %,respectively.From the point of view of nutrition,Salvelinus malma is a kind of fish with high nutritional value.2.The lamb Salvelinus malma has a “ U ” shaped stomach,19?30 pyloric caecum,with a thick short and no obvious bending of the intestine,which can be divided into the foregut and the hindgut with a ratio of 0.36 ± 0.08.The stomach has developed the muscle layer,with stomach gland,no goblet cells on the mucosal layer;the pyloric caecum fold distribution is more intensive,with obvious striate margin;the goblet cells in the intestinal tract are more intensive,and the posterior intestine is more distributed.The morphology and tissue structure of the three digestive organs of Salvelinus malma are adapted to their feeding properties.3.The p H of Salvelinus malma showed acidic 2.8,the pyloric caecum was neutral,the anterior and posterior intestines were weakly alkaline,and the p H values were 8.5 and 8.4.Among the three digestive organs of Salvelinus malma,the protease activity was the highest and the amylase activity was the lowest.The digestive enzyme activity was as follows: Amylase: pyloric caecum > anterior intestine > posterior intestine > stomach;Protease: anterior intestine > posterior intestine > pyloric caecum > stomach;Lipase: anterior intestine >posterior intestine> pyloric caecum> stomach.4.The optimum conditions for in vitro digestion of feed raw materials were as follows: p H values of gastric crude enzyme and intestinal crude enzyme digestion environment buffer were 2.8 and 8.5 gastric enzyme solution and intestinal enzyme solution usage were 5 m L and 10 m L;gastric digestion time was 8 h,intestinal digestion time was 15 h.Under the optimum in vitro digestion simulation conditions,the “ stomach-gut ” crude enzyme extract of Salvelinus malma of the flower lamb showed the best digestion of the two fish meal,and the digestibility of dry matter and protein was more than 67 %.In addition to 2 kinds of the fish meal,the soybean meal has the highest digestibility in vitro,its crude protein digestibility is more than 45 %,and dry matter digestibility is more than 37 %.Therefore,the soybean meal can be considered as feed raw material to replace part of fish meal.In conclusion,Salvelinus malma of flower lamb is a kind of fish with high nutritional value.Based on the analysis of external morphology and histology of stomach,pyloric sac and intestinal tract,the activity of three digestive enzymes and the ability of in vitro digestion of feed materials,Salvelinus malma is a typical carnivorous fish with strong protein digestion. |
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