| The experiment was conducted to investigate the enrichment of dietary n-3 PUFA indifferent tissues of broilers, and its effects on growth performance, body fat depositionand meat qualities in broilers, which will provide evidence of theory for producing thechicken meat enriched in n-3PUFA. Three hundred sixty 21-d-old Ross308 femalebroilers were divided into five groups, which were fed control diets (group 1), 3% linseedoil (3% LO, group 2), 5% linseed oil (5% LO, group 3), 5% micro-algae meal (5% MA,group 4) and 5% micro-algae meal +3% linseed oil (5% MA+3% LO, group 5) for 3weeks, respectively. The results were as follows:1. Enrichment of n-3 PUFA in different tissues of broilers. ALA, EPA, DHA contentsin liver were significantly increased and the n-6/n-3 ratio were significantly lowered(P＜0.05) with 3% and 5% LO (P＜0.01). The synthesis efficiency of ALA intolong-chain n-3 PUFA (EPA and DHA) was efficient in liver. The amounts of n-3PUFAin muscles of breast and thigh were increased significantly with 3% and 5%LO, mainlyin form of ALA and EPA (P＜0.05), while the amounts of DHA was not influenced(P＞0.05). The n-6/n-3 ratio were also significantly lowered (P＜0.01) and in muscles ofbroilers fed 5% LO diets presented higher values of n-3PUFA contents and lowern-6/n-3 ratio than those fed 3%LO; The amounts of DHA were increased significantlywhen 5% MA was fed (P＜0.05), whereas the total n-3PUFA were not increased and theratio of n-6/n-3 was higher than the other experiment groups (P＜0.05); In muscles ofbroilers fed 5% MA+3% LO, levels of DHA were similar to those fed 5% MA and theamounts of n-3PUFA and n-6/n-3 ratio were similar to those fed 3% LO (P＞0.05). LAand ALA were preferentially incorporated in muscles and abdominal fat, and long-chainPUFA, such as AA, EPA, DHA, in liver.2. Effects of n-3 PUFA on lipid synthetase activity of broilers. Serum levels of TG andLDL-C were not significantly different among groups (P＞0.05). The HDL-C level in 3%LO was significantly higher than the control (P＜0.05). The TC level was higher in serumof broiler fed 3%, 5% LO and 5%MA than the control, whereas in those fed 5% MA+3%LO, TC was lowered (P＜0.05). FAS activity in liver and LPL activity in abdominal fatwere lower in all experiment groups than the control (P＞0.05) which is disagreement withthe tendency of abdominal fat deposition.3. Effects of dietary n-3 PUFA on growth performance and carcass characteristics andmeat qualities of broilers. The results showed that it had no effect on final weight, dailygain and feed conversion with 3%, 5% LO and 5% MA (P＞0.05). Daily feed intake of 3% LO was significantly lower than the control (P＜0.01), but it was higher significantlywith 5% MA (P＜0.05). it had no effect on final weight, daily gain, daily feed intake andfeed conversion with 5% MA+3% LO (P＞0.05). Adominal fat percentage in 3% LO and5% MA+3% LO were lower significantly than the control (P＜0.05). The percentage ofeviscerated yield, breast muscle and leg musle were not affected by the dietary n-3 PUFA(P＞0.05). No significant differences in meat color, drip loss, pH value were detected in3% LO and 5% LO (P＞0.05), the lipid peroxidation level of chicken meat stored in 4℃increased significantly with 5% LO (P＜0.05).The conclusions were as follows:1. Using LO in broiler's diets can produce chicken meat enriched in high n-3PUFAand lower n-6/n-3 ratio, which can benefit human health as a source of riching inn-3PUFA food. The supplementation of LO in diet was not up to 5%.2. As a diet source which can supply DHA directly, MA produced the poor effect ofaggradation n-3PUFA. Further research is need to empolder the marine algae source richin high DHA and low in SFA. |
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