Effect Of Stocking Density And Environmental Enrichment Materials On The Welfare Level, Production Performance And Meat Quality In Broiler

Taking animal welfare as the point of view, this article synthesized the animal indicator of welfare level both domestic and overseas to investigate the effect of stocking density and environmental enrichment materials(EEM) on AA broilers'meat quality and production performance and welfare level by the way of experiment.The experiment birds were grouped in styles of 3(stocking density)×2(environmental enrichment materials) absolutely random and the density was 6,10,14 respectively. 1 perch,1 sand plate,2 colorized balls and 2 pieces of colorized string were placed in each treatments of EEM. At the beginning of the experiment, 816 of 21-days old healthy birds (Arbor Acres AA) were selected and distributed to 6 treatments with 4 replicates, which body weight was 696.29±1.56g. The experiment was designed to accomplish in four weeks. The broiler's behavior would be inspected on the first two days in the fourth week and the feather conditions score (FCS), gait score (GS) and tonic immobility (TI) of the brolier would also be asigned marks on the last two days before the experiment was ended. At last, 3 indivaduals chosed from each treatment would be weighed, blood sampled and slaughtered. The result showed that:Behavior analysis result indicated that high stocking density reduced the broiler's standing and grooming (P<0.05), and significantly increased the broiler's heat polyphea (P<0.01). Low stocking density significantly increased foraging (P<0.01). On the contrary, when the EEM was placed in, the heat polyphea decreased (P<0.01) and the dust bathing increased (P<0.01). At the same time, EEM made no obvious effects on unilateral wing-leg stretching, movement, drinking, feeding and attacking of the broiler (P>0.05). Increasing the stocking density resulted in a rising tendency of the TI time of broilers, and EEM helped to make the TI time trend to decrease (P>0.05).Appearance and skeleton character of the broilers showed that stocking density and EEM had significantly effect on FCS, GS and FA(P<0.05). In high stocking density treatment, the quantity of the broilers significantly decreased when FCS equaled to 1(P<0.05), and it increased when FCS equaled to 3(P<0.05); The quantity significantly decreased when GS equaled to 1 or 2(P<0.05), and it increased when GS equaled to 3 or 4(P<0.05). Once the EEM was placed in high stocking density treatment, the quantity of the broilers was significantly increased (FCS=1, GS=0) (P<0.05), and it decreased (FCS=3, GS>3) (P<0.05); High stocking density led to the increase of FA value of the broiler's leg length(P<0.05) and wing width(P<0.01), and the FA of leg width increased with rise of density (P<0.01); EEM helped to decrease the FA value of the leg lengthin n three different stocking density treament, and it also made the FA value of leg width and wing width in low and medium stocking density treatment slightly decreased (P>0.05).Blood index data showed that : With the stocking density increasing, the ratio of heterophil to lymphocyte (H:L) significantly increased(P<0.05), EEM helped to decrease the ratio in different stocking density; The stocking density and EEM had no clear effects on creatine kinase(CK)(P>0.05); In the four oxidation resistance indexes, MDA's contents in low stocking density significantly decreased(P<0.05), and GPX's activity significantly increased in high stocking density(P<0.05); The added EEM helped to increase the MDA's contents and GPX's activity in different treatments; The stocking density and EEM had no clear effects on T-AOC and SOD.Production performance and meat quality index data showed that: Increasing the stocking density would decrease the broiler's daily gain and feed intake significantly (P<0.01), and the ratio of the feed/meat ratio significantly increased (P<0.01). EEM helped decrease the mortality rate in high stocking density treatments, which had little effects on the performance of other indicators (P>0.01); the stocking density affected the carcass's property and the percentage of breast muscle and percentage of abdominal fat not very much(P>0.05)and adding EEM enabled to decrease the broiler's percentage of abdominal fat in different stocking density significantly (P<0.05), but it had little effect on other performance. With the stocking density increasing, the percentage of drip loss and cooking loss and the value of fleshcolor's a* significantly decreased (P<0.05), but it made no difference for other performance of the breast muscle's quality. EEM helped to make the value of the L* of the broilers in different stocking density significantly increased and IMP decreased (P<0.05), but it made no difference for other performance of the breast muscle's quality.