Omega-3 polyunsaturated fatty acids provided during embryonic development improve the growth performance and welfare of Muscovy ducks (Cairina moschata).

The welfare of ducks can be affected by unwanted behaviors such as excessive reactivity and feather pecking. Providing long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) during gestation and early life has been shown to improve the brain development and function of human and rodent offspring. The aim of this study was to test whether the pecking behavior of Muscovy ducks during rearing could be reduced by providing LC n-3 PUFA during embryonic and/or post-hatching development of ducklings. Enrichment of eggs, and consequently embryos, with LC n-3 PUFA was achieved by feeding female ducks (n-3F) a diet containing docosahexaenoic (DHA) and linolenic acids (microalgae and linseed oil). A control group of female ducks (CF) was fed a diet containing linoleic acid (soybean oil). Offspring from both groups were fed starter and grower diets enriched with DHA and linolenic acid or only linoleic acid, resulting in four treatment groups with 48 ducklings in each. Several behavioral tests were performed between 1 and 3 weeks of age to analyze the adaptation ability of ducklings. The growth performance, time budget, social interactions, feather growth, and pecking behavior of ducklings were recorded regularly during the rearing period. No significant interaction between maternal and duckling feeding was found. Ducklings from n-3F ducks had a higher body weight at day 0, 28, and 56, a lower feed conversion ratio during the growth period, and lower reactivity to stress than ducklings from CF ducks. Ducklings from n-3F ducks also exhibited a significantly reduced feather pecking frequency at 49 and 56 days of age and for the whole rearing period. Moreover, consumption of diets enriched with n-3 PUFA during the starter and grower post-hatching periods significantly improved the tibia mineralization of ducklings and the fatty acid composition of thigh muscles at 84 days of age by increasing the n-3 FA content.

Effects of dietary enrichment with n-3 fatty acids on the quality of raw and processed breast meat of high and low growth rate chickens.

1. The enrichment of raw poultry meat with n-3 fatty acids (n-3 FA) has been investigated in detail, particularly in high growth rate genotype standard broiler chickens, whereas low growth rate genotype Label Rouge chickens have received less attention. With the increased development of processed poultry products, it is necessary to ensure that the nutritional and sensory quality of meat enriched with n-3 FA is not affected by processing. 2. Two experiments were undertaken for this purpose. In the first experiment, 696 male Ross 708 chickens were reared under standard conditions, and in the second, 750 male JA 657 chickens were reared under Label Rouge conditions. All birds received the same starting and growing diets containing palm and soya oils in each experiment. Birds were distributed into three groups from 21 or 57 d of age for standard and Label Rouge chickens, respectively, and given a control, linseed oil or extruded linseed diet. Diets were also supplemented with vitamin E (100-200 mg/kg). Birds were slaughtered at 56 or 84 d of age for standard and Label Rouge chickens, respectively. A total amount of 60 kg of breast meat from each group was processed into white cured-cooked meat. 3. The dietary treatment had no effect on the growth performance of chickens or meat yield. The use of extruded linseed or linseed oil only decreased the carcass fatness of the standard chickens but had no effect on the carcass fatness of Label Rouge chickens. The nutritional quality of raw and cured-cooked meat was improved (increased concentration of n-3 FA), whereas the technological quality of the meat (pH, juice loss after cold storage, susceptibility to oxidation, colour, processing yield and shear force value) and sensory quality of the processed products were not or slightly affected. 4. Linked to lower breast yield, to lower lipid content in breast meat and to higher slaughter age, Label Rouge chickens seemed to be less efficient for n-3 FA deposition in breast muscles than standard chickens.

Modulation of glycogen and breast meat processing ability by nutrition in chickens: effect of crude protein level in 2 chicken genotypes.

The aim of the study was to evaluate the impact of 2 isoenergetic growing diets with different CP (17 vs. 23%) on the performance and breast meat quality of 2 lines of chicken divergently selected for abdominal fatness [i.e., fat and lean (LL) lines]. Growth performance, breast and abdominal fat yields, breast meat quality parameters (pH, color, drip loss), and muscle glycogen storage at death were measured. Increased dietary CP resulted in increased BW, increased breast meat yield, and reduced abdominal fatness at slaughter regardless of genotype (P < 0.001). By contrast, dietary CP affected glycogen storage and the related meat quality parameters only in the LL chickens. Giving LL chickens the low-CP diet led to reduced concentration of muscle glycogen (P < 0.01), and as a result, breast meat with a higher (P < 0.001) ultimate pH, decreased (P < 0.001) lightness, and reduced (P < 0.001) drip loss during storage. The decreased muscle glycogen content observed in LL receiving the low-CP diet compared with the high-CP diet occurred concomitantly with greater phosphorylation amount for the α-catalytic subunit of adenosine monophosphate-activated protein kinase and glycogen synthase. This was consistent with the reduced muscle glycogen content observed in LL fed the low-CP diet because adenosine monophosphate-activated protein kinase inhibits glycogen synthesis through its action on glycogen synthase. Our results demonstrated that nutrition is an effective means of modulating breast meat properties in the chicken. The results also highlighted the need to take into account interaction with the genetic background of the animal to select nutritional strategies to improve meat quality traits in poultry.

Influence of increasing slaughter age of chickens on meat quality, welfare, and technical and economic results.

Because of the increasing demand for raw cuts and processed products, there is a trend to producing very heavy broilers. Breeds that are used for such kinds of production have been intensively selected for growth rate and breast meat yield, and birds are reared for a longer period than standard broilers. This study was to evaluate the effects of increasing slaughter age on technical and economic factors, including production efficiency and environmental costs, bird welfare, and breast meat quality in a modern heavy broiler line. Five groups of 300 male Ross 708 chickens were reared until slaughter ages of 35, 42, 49, 56, or 63 d. Increasing age at slaughter from 35 to 63 d resulted in a 7.4-fold increase (P < 0.01) in mortality rate (5.21 vs. 0.70%). It also increased (P < 0.001) the slaughter weight and ADFI of birds 2.5- and 1.4-fold, respectively, without affecting their G:F. Under our experimental conditions, economic profit evaluated through the net gain reached a maximum at 42 d. The moisture and ammonium content of litter increased (P < 0.05 and P < 0.01, respectively) rapidly during rearing concomitantly with increased (P < 0.05) occurrence and severity of contact dermatitis and decreased (P < 0.05) walking ability and activity of birds. Thermal comfort also decreased (P < 0.05) greatly as early as 42 d of age. Changes in carcass quality occurred mainly between 35 and 56 d of age, with a progressive increase (P < 0.001) in breast and leg yield, whereas body fatness was barely affected by age. Major changes in breast meat traits were observed between 35 and 49 d of age, with an increase in muscle pH at 15 min (P < 0.01) and 24 h (P < 0.001) postmortem and reduced (P < 0.001) lightness and drip loss. The protein and lipid content of raw breast meat also increased (P < 0.05 and P < 0.01, respectively) with age. Taking into account the main aspects of sustainability, we could recommend slaughtering chickens of heavy line at 42 d of age.

Consequence of muscle hypertrophy on characteristics of Pectoralis major muscle and breast meat quality of broiler chickens.

The structural and metabolic characteristics of the pectoralis major (P. major) muscle (i.e., breast muscle) and the quality of the resulting meat were studied in relation to breast muscle fiber development in broiler chickens. Six hundred birds originating from a commercial, grand parental, male heavy line (Hubbard-Europe, Châteaubourg, France) were kept under conventional breeding methods until their usual marketing age of 6 wk. For all birds, the plasma creatine kinase activity and the P. major muscle fiber cross-sectional area (CSA), glycolytic potential, lactate content, pH at 15 min postmortem, as well as the ultimate pH, CIELAB color parameters [lightness (L*), redness (a*), and yellowness (b*)], and drip loss of breast meat, were measured. Increased breast weight and yield were associated with increased fiber CSA, reduced muscle glycolytic potential, and reduced lactate content at 15 min postmortem. Therefore, P. major muscle exhibiting larger fiber CSA exhibited greater pH at 15 min postmortem and ultimate pH, produced breast meat with lower L* and reduced drip loss, and was potentially better adapted to further processing than muscle exhibiting small fiber CSA.