Effect of reduced dietary protein and supplementation with a docosahexaenoic acid product on broiler performance and meat quality

Abstract

1. Chicken breast meat is a lean meat due to its low content of intramuscular fat (IMF) resulting in an overall lower acceptability by consumers due to a decrease in juiciness, flavour and increased chewiness. Recently, studies performed in pigs suggested the possibility of increasing IMF by decreasing dietary crude protein (CP) content, an effect possibly mediated through an increased lipogenesis.

2. Dietary supplementation with lipids rich in omega 3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) may modulate an increase in the content of these fatty acids in meat from monogastric animals and, thus, promote the daily intake of n-3 LC-PUFA by humans.

3. LC-PUFA are very susceptible to oxidation, resulting in off-flavours that affect meat quality and consumers’ acceptability.

4. This trial was conducted to assess the effect of reducing dietary CP, from 21% to 17%, on chicken’s meat IMF content and, simultaneously, to evaluate if a complementary supplementation with a proprietary n-3 LC-PUFA source (DHA Gold™) could improve meat quality. These effects were assessed by measuring productive performance and meat quality, oxidative stability, sensory traits and fatty acid profile.

5. A reduction in CP content of broiler diets, from 21% to 17%, balanced for lysine, improved performance while it was not sufficient to increase IMF content in chicken meat. In contrast, DHA Gold™ supplementation had a positive impact both in broiler productive parameters and in meat fatty acid profile.

6. In addition, incorporation of 7.4% of DHA Gold™ in the diet promoted carcass yield but negatively affected chicken meat acceptability by consumers, due to a decrease of meat oxidative stability.

7. Overall the data suggest that neither a dietary supplementation with DHA Gold™ nor a reduction in CP have a direct positive effect in the levels of IMF present in broiler meat.

ACKNOWLEDGEMENTS

We thank Sociedade Agrícola da Quinta da Freiria SA (Bombarral, Portugal) for supplying the one-day-old broilers used in this experiments, Novus International (St. Charles, USA) for the generous gift of DHA Gold™ used in this experiment, and Clínica Médica e Diagnóstico Dr. Joaquim Chaves (Algés, Portugal) for the technical assistance regarding serum lipids determination. We also acknowledge all the members of Meat Sensory Panel of Faculdade de Medicina Veterinária (Lisboa, Portugal).