Effects Of Coated Trace Minerals On The Performance And Health Of Broilers

In this study,two experiments were conducted to investigate the energy-saving and emission-reducing effects of coated trace minerals in broiler chickens from aspects of production performance,slaughter performance,tibia quality,intestinal structure and function,antioxidant capacity,contents of trace elements in tissues and excreta,and to explore the appropriate level of coated trace minerals.Experiment 1: Effects of coated trace minerals on the performance and health of broilers under different oil level of feedThe purpose of this experiment was to study the effects of coated trace elements on the performance and health of broilers,and to provide data support and theoretical basis for the rational application of coated trace elements in broilers.A 2 × 3 factor design was used in the experiment.960 1-day-old AA broilers were randomly divided into 6 treatments with 8 replicas in each group and 20 in each group.Trial diet with 2 oil levels: 5% and 1.5%;three trace minerals treatments: NRC recommended level group(inorganic source;The supplyments of Cu-Fe-Mn-Zn-Se-I-Co is 8-80-60-40-0.15-0.35-0.15 mg/kg respectively),coated group and uncoated group.The trace elements of the coated group and the uncoated group are both inorganic sources,and the levels of trace minerals are the same: The supplyments of Cu-Fe-Mn-Zn-Se-I-Co is 2.5-35-30-30-0.2-0.2-0.15 mg/kg respectively.The experiment lasted 42 days.The diets were prepared according to two stages(1 ~ 21 days in the early stage and 22 ~ 42 days in the later stage).The nutrient composition and energy of the six treatments were the same except for the trace minerals.The results show that: 1)the growth performance of broilers was significantly improved by 5% oil level;2)compared with NRC group,the growth performance of broilers was not significantly affected by coated and uncoated diets,however,the coated group had certain advantages,BW and BWG of broiler chickens in the coated group increased by 2% and FI increased by 1% on 42d;3)in the coated group,the villus height of jejunum and ileum in each stage were significantly increased(P < 0.05),and the villus height / crypt depth in jejunum and ileum of broilers was significantly increased(P < 0.05).Compared with NRC group,there was no significant difference in intestinal relative length and weight between coated group and uncoated group;4)the contents of ash,calcium and phosphorus in tibia of broilers were significantly increased by coated minerals(P < 0.05).Compared with NRC group,there was no significant difference in tibia length and strength between coated group and uncoated group.5)Compared with NRC group,the contents of trace minerals in coated group and uncoated group decreased significantly(P < 0.01).On the 21 d,the contents of trace minerals in coated group decreased 54%,23%,7% and 35% respectively,while those in uncoated group decreased 65%,20%,10% and 34% respectively;On the 42 d,those in coated group decreased 38%,28%,25% and 35% respectively,those in uncoated group decreased by 46%,27%,26% and 38% respectively.In conclusion,reducing the level of trace minerals in broiler diet had no significant effect on the performance of broilers and significantly reduced the content of trace minerals in excreta.Compared with uncoated group and NRC group,the coated group could improve BW,BWG and FI of broiler at different stages to a certain extent.The coated trace minerals can improve the intestinal morphology and increase the deposition of calcium and phosphorus in tibia of broiler.Experiment 2: Study of the suitable level of coated trace minerals in broilers feedThe aim of this experiment is to study the suitable dietary level of coated trace minerals.The 2×4+3 factor design was used in the experiment.2200 1-day-old Ross 308 broilers were randomly divided into 11 treatments with 10 repeats in each group(5 as male and 5 as female),and 20 chickens in each group.The trial consisted of three control groups: Blank group(basic diet without trace minerals);NRC group(inorganic source: The supplyments of Cu-Fe-Mn-Zn-Se-I-Co is 8-80-60-40-0.15-0.35-0.15 mg/kg respectively);2NRC group(inorganic source: levels of trace minerals are twice as high as those in NRC);the main effect includes two kinds of trace minerals products: uncoated and coated trace minerals.Four kinds of level of addition of trace minerals: 250mg/kg group(The supplyments of Cu-FeMn-Zn-Se-I-Co is 2.5-35-30-30-0.2-0.2-0.15 mg/kg respectively);350mg/kg group(The supplyments of Cu-Fe-Mn-Zn-Se-I-Co is 3.5-49-42-42-0.28-0.28-0.21 mg/kg respectively);450mg/kg group(The supplyments of Cu-Fe-Mn-Zn-Se-I-Co is 4.5-63-54-54-0.36-0.36-0.27 mg/kg respectively),550mg/kg group(The supplyments of Cu-Fe-Mn-Zn-Se-I-Co is 5.5-77-66-66-0.44-0.44-0.33 mg/kg respectively).The experiment lasted for 33 days.The diets were prepared according to two stages(1 ~ 21 days in the early stage and 22 ~ 33 days in the later stage).The nutrient composition and energy of the 11 treatments were the same except for the trace minerals.The results show that: 1)There was no significant difference in BW,BWG,FI and slaughtering performance among each group.Compared with the 2NRC group,the coated groups could significantly reduce the FCR of 22-33 d broilers(P < 0.05).2)Compared with the uncoated group,the MDA content of breast muscle of the 33 d broilers in the coated group decreased significantly(P < 0.05),the MDA content in the liver of the 21 d broiler decreased significantly(P < 0.05),and the serum MDA content of the coated broiler decreased significantly compared with the 2NRC group(P < 0.01).Compared with the blank group,the GSH-PX activity of breast muscle of 33 d broilers(P < 0.05),liver GSH-PX activity of 21 d broilers(P < 0.01)and serum GSH-PX activity of 21 d,33d broilers(P < 0.01)among each group were significantly increased.3)compared with the uncoated group,the activities of lipase of duodenum and jejunum in the coated group increased significantly(P < 0.05);compared with the 2NRC group,and the activity of lipase of duodenal in the coated group increased significantly(P < 0.01).4)Compared with the uncoated group,the coated group increased the villi height of duodenum and jejunum of 21 d broilers(P < 0.05),and the V/C of ileum of 21 d broilers and 33 d broilers significantly(P < 0.01).The crypt depth of duodenum and ileum was significantly decreased(P < 0.05).Compared with the blank group and NRC group,the ileum crypt ratio of 21 d broilers of the coated group was significantly increased(P < 0.05).5)Compared with the uncoated group,the coated group increased the content of Fe in the liver and the content of Cu in serum of 33 d broilers significantly(P < 0.05).In conclusion,the addition of trace minerals can significantly improve FCR of broilers at different stages with the improvement of the activity of GSH-PX in broilers.Compared with NRC recommendation level,the addition of lower level of trace minerals did not resulted the decrease of growth performance in broiler,but decrease the content of trace mineral in feces.Compared with uncoated group,the coated trace mineral could improve the broiler growth performance in some extent with the decrease of MDA content in broilers and increased of the villus height and the ratio of villus to crypt,decreased the depth of crypt,effectively improved the intestinal morphology,and increased the activity of intestinal lipase,which was conducive to the digestion and absorption of small intestine.Taking FCR as the index,the recommended level of coated trace mineral was 350 mg/kg,and uncoated trace minerals was 450 mg/kg;Taking the activity of enzymes related to antioxidant capacity and the content of MDA in broiler chickens as an index,the recommended level of coated trace minerals was 250 mg/kg,uncoated trace minerals was 350 mg/kg;Taking intestinal morphology of broilers at different stages as the index,the recommended level of coated trace minerals was 250 mg/kg.