Cecilia Mugnai

EFFECT OF ORGANIC PRODUCTION SYSTEM ON BROILER CARCASS AND MEAT QUALITY

The effect of organic production on broiler carcass and meat quality was assessed. Two hundred and fifty Ross male chickens were assigned to two different systems of production: conventional, housing in an indoor pen (0.12 m(2)/bird); organic, housing in an indoor pen (0.12 m(2)/bird) with access to a grass paddock (4 m(2)/bird). At 56 and 81 days of age, 20 chickens per group were slaughtered to evaluate carcass traits and the characteristics of breast and drumstick muscles (m. pectoralis major and m. peroneus longus). The organic chickens had carcasses with a higher breast and drumstick percentages and lower levels of abdominal fat. The muscles had lower pHu and water holding capacity. Instead cooking loss, lightness values, shear values, Fe, polyunsaturated fatty acids of n-3 series and TBA-RS were higher. The sensory quality of the breast muscle was better. Organic production system seems to be a good alternative method, due to better welfare conditions and good quality of the carcass and meat. A negative aspect was the higher level of TBA-RS in the muscles, probably due to greater physical activity.

Rearing rabbits on a wire net floor or straw litter: behaviour, growth and meat qualitative traits

The effect of three housing systems and two stocking densities on the growth performance in fryer rabbits and qualitative traits of meat was investigated. Three hundred hybrid males, 35 days old, were randomly assigned to one of three housing conditions: conventional bicellular cages, a straw-bedded pen or a wire-netted pen. The stocking densities were 16.6 rabbits/m2 in cages and 10.2m2 in pens. The trial lasted 50 days. Pen raised rabbits showed lower growth rate, and higher feed:gain ratio and mortality, than those held in cages. The slaughter traits — dressing out percentage, meat:bone ratio, carcass compactness and fatness — confirmed a lower maturity of these animals. The longissimus lumborum muscle had lower pHu (ultimate pH) and redness, higher lightness; TBA-RS (thiobarbituric reactive substances) were superior in spite of higher antioxidant capacity in vivo. The rabbits raised in straw-bedded pens gave the poorest results due to straw ingestion and more direct contact with excreta. Rearing rabbits in indoor wire netted pens is a possible alternative housing system to improve the rabbit’s welfare.

Performance and behaviour of chickens with different growing rate reared according to the organic system

Abstract The performance and the behaviour of three different chicken strains, reared according to the EEC-Regulation 1804/1999 on organic system, were compared. The strains had very slow (Robusta maculata), slow (Kabir) and fast (Ross) growing rates, respectively. The trial was carried out on 200 chickens (male and female) per strain. Rearing lasted 81 days as required by the EEC Regulation. At slaughter age, 20 birds per group were killed. Robusta maculata and Kabir chickens showed more intense walking activity and better foraging aptitude; their antioxidant capacity was also superior. Ross chickens had a good growth rate and feed conversion index, reaching an excellent body weight, but the mortality and the culling rate were high indicating that fast-growing strains do not adapt well to organic production. Robusta maculata showed the worst productive performance although the mortality was low and Kabir birds gave intermediate results. The carcass traits were the best in Ross and the poorest in Robusta maculata. Male chickens were heavier and leaner than females.

Effect of genotype and rearing system on chicken behavior and muscle fiber characteristics

The effect of the organic production system and genotype on chicken behavior and muscle fiber characteristics was assessed. Three hundred day-old male chicks from slow-growing (Leghorn), medium-growing (Kabir), and fast-growing (Ross 208) genotypes were assigned to 2 different production systems: conventional, housing in an indoor pen (0.12 m(2)/bird); and organic, housing in an indoor pen (0.12 m(2)/bird) with access to a grass paddock (4 m(2)/bird). Behavioral observations were recorded from 73 to 80 d of age in the morning and afternoon. At 81 d of age, blood samples were collected to measure lactate dehydrogenase and creatine kinase, and 20 birds per strain and rearing system were slaughtered. Samples of pectoralis major, ileotibialis lateralis, and semimembranosus muscles were obtained for histological evaluations. Behavioral observations showed that genetic selection of animals for a better growth rate modified their behavior, reducing kinetic activity. Indeed, Leghorn birds were characterized by moving activities, whereas Kabir and Ross strains were discriminated on the basis of their lying, standing, and eating activities, and these activities were strongly associated with energy conservation, growth, and muscle fiber characteristics. Fiber characteristics and muscle enzyme functions were affected by rearing system only in animals adapted to the organic system. Interesting results relative to Leghorn chickens are the presence of alpha-Red fiber in breast muscle and the increased cross-sectional area of the ileotibialis lateralis muscle, which together with behavioral data could affirm that this genotype is the most adapted to the organic rearing system.

Comparison of two chicken genotypes organically reared: oxidative stability and other qualitative traits of the meat

Abstract The effect of genotype on the oxidative stability and other qualitative traits of chicken meat was studied. Two groups of 200 chicks (Ross 205 and Kabir) were reared according to the organic farming system. At 81 d of age 20 birds per group were slaughtered and after refrigeration (24 h at 4°C) of the carcasses, Pectoralis major muscles were excised for analyses. Samples were analysed after 0, 24, 48, 72 and 96 hours of storage at 4°C under continuous fluorescent illumination (2300 lux). The analyses concerned the chemical composition and the shear force (only at time 0) and the progress of several traits as pH, CIELAB values, Thiobarbituric Acid Reactive Substances (TBARS), panel test and fatty acid composition (at 0 and after 96 h). Genotype greatly affected the physico-chemical characteristics and the sensory evaluation. The meat from Ross chickens showed high TBARS values, perhaps due to selection for growth rate that reduced their adaptability to greater space allowance and to poorer environmental conditions; these higher TBARS values were also negatively correlated to lightness and yellowness. The initial level of TBARS affected the oxidative stability of breast meat during storage. The amount of TBARS showed significantly negative relationship with the sensory evaluation; breast meat of Kabir had higher scores for liking when the level of malondialdehyde (MDA) was less than 2.5 mg kg-1.

Effect of rearing system and season on the performance and egg characteristics of Ancona laying hens

Abstract Productive performance and egg characteristics of Ancona laying hens reared under three different rearing systems (conventional, organic and organic-plus) were compared during an experimental period of one year. Three-hundred-sixty Ancona female chicks at 28 days of age were divided in three groups and assigned to different rearing systems. The organic group had 4m2 pasture/hen according to the requirements imposed by the EC Regulation 1804/99, whereas the organic-plus group had a larger grass paddock (10m2/hen). The Control group was reared in cages under standard housing conditions. The following egg characteristics were recorded and analysed during the year-long cycle: egg weight and egg mass laid/d, weight of egg components, shell thickness, Haugh index and yolk colour. Egg quality was affected by the pasture available. The hens that ingested grass (organic-plus), produced eggs with higher shell weight and percentage, darker yolk colour and higher α-tocopherol, carotenoid and polyphenol contents. The other egg traits were not affected by rearing system.

Comparison of different reproduction protocols for rabbit does: effect of litter size and mating interval

The aim of the study was to compare different reproductive protocols based on fixed (11 days after kindling) or alternating remating intervals (1 day post-partum and post-weaning alternatively) and two litter sizes (six vs. eight kits). Weaning of kits occurred at 26 days of age. Four groups of 35 New Zealand White females were inseminated for eight consecutive cycles. Does with six kits had a higher sexual receptivity, fertility rate and a lower energy deficit. The milk production was lower but the milk suckled per kit was higher. This greater milk availability determined heavier kits till 70 days of age and a lower mortality rate. Does submitted to the alternating rhythm showed the same kindling interval as the respective fixed groups although the mating interval was 3 days longer. This rhythm in comparison with the fixed one seemed more adapted to doe physiology and improved the receptivity and the fertility, even under more critical conditions (high milk output).

Fatty acid composition of meat and estimated indices of lipid metabolism in different poultry genotypes reared under organic system

According to EC regulation 889/08, different European countries should draw up a list of slow-growing strains adapted to an organic system, and in the meantime, provide this information to operators and the European Union commission. Thus, the aim of the present work was to evaluate the effect of poultry genotype on fatty acid composition and lipid indices of poultry meat. Six poultry genotypes (100 birds each), each with a different growth rate (slow-growing: Leghorn, Ancona, Cornish×Leghorn; medium-growing: Kabir, Naked neck; fast-growing: Ross), were reared under an organic system. Breast meat fatness, fatty acid composition, and indices were largely related to genotype, as slow-growing strains had higher elongase, thioesterase, and Δ5/Δ6 desaturase indices accompanied by a lower Δ9. Differences in the fatty acid profiles were observed by varying contents of total saturated fatty acids, with a higher value seen in Leghorn chickens and a lower value seen in commercial lines. On the contrary, Leghorn and Ancona chickens exhibited higher amounts of stearic acid and total polyunsaturated fatty acids compared with commercial genotypes, both in the total content and in the different fractions (total n-3 and total n-6). Despite the increased consumption of fresh forage, the lower linolenic acid in meat of the slow-growing strain could be explained by the higher conversion of this fatty acid to its long-chain derivatives.

Effect of dietary supplementation of Spirulina (Arthrospira platensis) and Thyme (Thymus vulgaris) on rabbit meat appearance, oxidative stability and fatty acid profile during retail display

The objective of this study was to evaluate the effect of Spirulina and Thyme supplementation on rabbit meat during retail display. At weaning 294 rabbits were allocated to 7 different treatments (42 rabbits/treatment). Rabbits of the control group (C) received a diet without any supplementation throughout the experiment (5-11 weeks of age). The other groups were fed diets containing 5% Spirulina (S), 3% Thyme (T) or both supplements (ST) for the whole trial (5-11 weeks; treatments S, T and ST), or for a part of the growing period (8-11 weeks; treatments C-S, C-T and C-ST). Colour parameters, pH, water holding capacity and drip loss were determined on fresh and stored Longissimus dorsi muscle of 5 rabbits/treatment. Spirulina- and Thyme-supplemented diets had a significant effect on redness and yellowness of Longissimus dorsi. Drip loss was significantly reduced in C-T and T groups that also showed the highest content of α-tocopherol and n-3 fatty acids content and the lower lipid oxidation.

Effect of dietary alfalfa on the fatty acid composition and indexes of lipid metabolism of rabbit meat

The objective of the study was to analyse and increase the quality of rabbit meat by increasing the levels of natural bioactive compounds through providing fresh alfalfa to rabbits as complementary feed. At 50 days of age, forty rabbits were divided into two homogeneous groups and fed pelleted feed (control group) or pelleted feed plus fresh alfalfa (alfalfa group). The lipid content of meat was significantly higher in the control group likely due to the higher feed consumption observed in this group. The same trend was observed in the contents of myristic, palmitoleic, oleic and linoleic acid. On the contrary, the supplementation of fresh alfalfa increased the stearic, linolenic, eicosatrienoic, eicosapentaenoic, docosapentaenoic, docosahexaenoic and total polyunsaturated fatty acid contents; also the total monounsaturated fatty acids and the α- and γ-tocopherol content was significantly lower. Moreover, alfalfa ingestion decreased the n-6 content, n-6/n-3 ratio and thrombogenicity index.