Digestive Characteristics Of Diets With Different Starch Sources And Their Effects On Growth And Glucose Metabolism Of Geese

Starch is the primary source of energy for poultry,and there are differences in the digestion characteristics of different types of starch.Different starch compositions of diets grain will directly affect the release rate of glucose in the intestinal of geese.The timely and adequate supply of glucose can save oxidation function amino acids’ and promote growth and development of geese.At present,there are few studies on the digestive characteristics of different starch sources and their effects on growth geese.This experiment systematically aimed to study the structural aspects of different starch source diets and their impact on growth performance and glucose metabolism in geese through in vitro digestion tests and animal tests.This study provide a reference for better use of starch source characteristics to allocate geese diets accurately.1.Structural properties and digestive properties of different starch sourcesFirstly,starch extraction and purification of glutinous rice,indica rice,corn,and high amylose were carried out,the starch grain morphology of different feed raw materials was observed,and the structural characteristics of different starch sources were studied.Then,four other starch source feeds were prepared,namely glutinous rice group,corn group,indica rice group,and high amylose group.In vitro digestion experiments were used to simulate the digestion process of starch in the intestine,and the glucose release rate of different starch source diets was explored.The results showed that:(1)The particle size of four starches:glutinous rice≈indica rice<corn<high amylose(P<0.05).There are significant differences in the microstructure of starch grains of different feed grain raw materials;the starch grain of glutinous rice was a porous polyhedron with a surface,the starch grain of indica rice was a polyhedron with a smooth and dense consistency,corn starch was an ellipsoid with a smooth surface,and high amylose was an irregular polyhedron with a smooth surface.(2)The starch digestibility of glutinous rice feed grain was high,and the increase and decrease rates are large.The starch digestibility of indica and corn diets was relatively stable,and the starch digestibility of indica rice diets was higher than that of corn and high amylose diets.2.Effects of different starch source diets on growth performance and glucose metabolism of geeseA total of 240 healthy 35-day-old Jiangnan white geese with similar body weights were randomly divided into four experimental groups(glutinous rice group,corn group,indica rice group,and high amylose group)with six replicates per group and ten geese per replicate.The experimental diet was the same as that in experiment 1.The pre test period was seven days,the trial period was 28 days,and formal trials began at 35 days of age.The dynamic blood glucose monitoring was carried out on 62 days.The blood glucose meter was used to measure blood glucose at 60 min before feeding(fasting state)and 15 min,30 min,60 min,120 min,180 min,240 min,300 min,and 360 min after feeding,respectively.Growth performance and glucose metabolism of geese at 63 days were determined.The results showed that:(1)After feeding different diets,the blood glucose concentration of the geese in the indica group and the corn group increased relatively slowly and steadily,the blood glucose of the geese in the glutinous rice group rose the fastest.The blood glucose concentration of geese in the high amylose group remained at a low level.The blood glucose concentration of geese in the four experimental groups had the most significant difference 30 minutes after feeding intake(P<0.05).Different times after feeding intake significantly affected the rate of blood glucose increase(P<0.05).The blood glucose concentration increased significantly from fasting to 30 minutes after feeding intake and decreased significantly from 30 to 300 minutes after feeding.Blood glucose concentration increased the fastest 15～30 minutes after feeding(P<0.05).(2)The geese in the indica rice group had the largest body weight at 63 days and was significantly higher than that in the high amylose group(P<0.05).The pancreas,jejunal chyme and jejunal mucosal α-amylase activities in the indica and high amylose groups were significantly lower than that in the glutinous rice group(P<0.05).(3)The blood glucose content of geese in the indica group,corn group,and high amylose group was significantly lower than that in the glutinous rice group(P<0.05).The serum total cholesterol content of geese in the glutinous rice and corn groups were significantly higher than that in the high amylose group(P<0.05).The serum triglycerides and lactic acid contents of the geese in the indica rice and the high amylose groups were significantly lower than those in the glutinous rice group(P<0.05).The serum insulin content of geese in the glutinous rice group was significantly lower than that in the corn group,and the high amylose group(P<0.05),and the content of glucagon was significantly higher than that in the corn group(P<0.05).The liver glycogen content of the geese in the indica,corn,and high amylose groups were significantly lower than that in the glutinous rice group(P<0.05),The activity of hepatic glucose-6phosphate dehydrogenase in the glutinous rice group was significantly higher than that in the high amylose group(P<0.05),and the content of glycogen synthase kinase-3β was significantly lower than that in the high amylose group(P<0.05).3.Effects of different starch source diets on slaughter performance,meat quality and nutrient availability of geeseAt 63 days of the geese,body size traits,slaughter properties and meat quality were determined.The metabolic test was carried out by Total Collection Method by selecting one geese near average body weight from each replicate.The results showed that:(1)There were no significant differences in body size traits among all groups(P>0.05),The abdominal fat percentage of geese in corn group and high amylose group was significantly lower than that in the glutinous rice group(P<0.05).(2)Pectoral muscle L*in glutinous rice and indica rice groups was significantly higher than that in the corn group(P<0.05),breast muscle a*of geese in the corn group was significantly higher than that in glutinous rice group(P<0.05).The content of PUFA n-6 and n-6/n-3 in the breast muscle of indica rice,corn,and high amylose groups were significantly lower than those in the glutinous rice group(P<0.05).The fiber diameter of breast muscle in corn and indica rice groups was significantly higher than that in the high amylose group(P<0.05).The fiber density of breast muscle in the glutinous rice and high amylose groups was significantly higher than those in the corn and indica rice groups(P<0.05).(3)The total starch utilization rate of geese in glutinous rice group was significantly higher than that in other groups(P<0.05).The crude protein utilization rate of the glutinous rice group was higher than those in the corn group and high amylose group(P<0.05).The methionine utilization rate of geese in the corn and glutinous rice groups was higher than those in the indica rice and high amylose groups(P<0.05).The lysine utilization rate of indica rice and glutinous rice groups was higher than those in the corn and high amylose groups(P<0.05)To sum up,the starch digestion rate is vary in different sources of starch grain size and shape.Different starch source diets affect the digestion and absorption of glucose and amino acids by changing the starch digestion rate(changing energy supply)in the digestive tract of goslings,affecting the blood glucose balance and liver glucose metabolism goslings,and ultimately affect the growth performance of geese.High amylose diet can lead to an insufficient intestinal energy supply and reduce the growth performance of geese.Corn and indica rice diets can release glucose continuously and stably in the intestine to maintain a good blood glucose dynamic balance,which positively affects growth performance in geese.Therefore,indica rice can replace corn as a starch source for the diet preparation of geese.