A. Dal Bosco

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.

Effect of dietary vitamin E on the oxidative stability of raw and cooked rabbit meat

The effect of dietary α-tocopheryl acetate supplementation (200mg/kg diet) on plasma and muscle levels of α-tocopherol and the oxidative stability of raw and cooked rabbit meat was determined. Two groups of 20 male hybrid rabbits were fed the experimental diets from 35 to 80 days of age. Feed intake, live weight, feed efficiency and qualitative traits of the carcass and meat were recorded. The α-tocopherol levels in plasma and muscle were significantly higher (p≤0·01) in the supplemented group, which also showed an increase in oxidative stability in both raw and cooked meat. The higher α-tocopherol level improved the physical traits of the meat, significantly reducing shear value and increasing water-holding capacity; n-3 fatty acids in raw and cooked meat increased (p≤0·05) and the thrombogenic index decreased (p≤0·05). Dietary vitamin E did not influence weight gain, feed intake and dressing yield.

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.

Effects of flaxseed dietary supplementation on sperm quality and on lipid composition of sperm subfractions and prostatic granules in rabbit

Lipids are the main structural/functional components of the sperm, and their composition may undergo a series of modifications in relation to either physiologic events (capacitation and acrosome reaction) and/or diet. The goals of the current study were (1) to investigate whether a flaxseed (FS) dietary supplementation could affect the lipid and fatty acid profile of sperm subfractions and of prostatic granules (PGs) and (2) to evaluate the effects of dietary FS on rabbit buck semen quality. Accordingly, 20 adult New Zealand White rabbits were fed ad libitum a control diet (CO) or a diet supplemented with 5% extruded FS. Integration of diet with FS, as a consequence of the linolenic acid (C18:3n-3; LNA; 56%), increased the dietary n-3/n-6 ratio and resulted in a substantial rearrangement of sperm fatty acid composition at the subcellular level, mainly of polyunsaturated fatty acid (PUFA)n-3 (8.3% vs. 14.3%, P<0.05). The lipid and fatty acid profiles of sperm tail membrane were the most affected, undergoing the following significant changes: (1) a reduction by half of linoleic acid (C18:2n-6; LA) and docosapentaenoic acid (22:5n-6; DPA), and a reduction of cholesterol (-70%); (2) a concomitant increase of LNA (+65%), docosahexaenoic acid (22:6n-3; DHA; +83%), and of oleic acid (C18:1n-9, +61%). As a consequence, the sperm of FS-fed rabbits had a twice higher n-3/n-6 ratio and phospholipid/cholesterol ratio compared with the control sperm. These changes might have been on the basis of the higher responsiveness to hypo-osmotic solution and, hence, the higher sperm track speed observed for the FS group. Also, the membrane integrity and viability of the LNA-enriched sperm were both improved. On the other hand, the presence of lignans in FS might have accounted for the reduction of sperm cholesterol in the semen of FS-treated rabbits. The responsiveness of sperm to acrosome reaction was not affected by the dietary treatment probably due to supranutritional level of vitamin E and to the higher number of PGs, which are known to play a key role in sperm capacitation. In conclusion, our data showed for the first time that the integration of FS into the rabbit diet may improve sperm quality by modifying the sperm lipid composition and that the sperm subfractions and the PGs respond differently to the FS-induced lipid manipulation.

Effect of dietary supplementation with olive pomaces on the performance and meat quality of growing rabbits

The aim was to investigate the effects of three types (A, B and C) of stoned and dehydrated olive pomaces (OPs), differing in olive cultivar, on productive performance and meat quality of growing rabbits. The inclusion of OPs (5%) negatively affected the performance of rabbits as it reduced the feed intake, growth rate, carcass weight and dressing out percentage (P<0.05). Compared with the control, the meat of OP rabbits had a greater amount of monounsaturated and a lower amount of polyunsaturated fatty acids (P<0.05), independent of the type of OP used. Oxidative processes in the meat of OPA and OPB were higher (P<0.05), whereas OPC showed the same levels as the control group. This was due to the higher total polyphenol concentration and to the concomitant lower peroxide value of OPC. These results recommend the use of OP in rabbit diet with caution, taking into account the quality of the by-product in terms of oxidative status.

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.

Pasture-based systems for poultry production: implications and perspectives

The use of pasture-based systems for poultry production is growing due to consumer demand for specialty ‘natural’ and ‘welfare-friendly’ meat and eggs. This paper discusses the various meanings of the term ‘pastured poultry’ and defines the different pasture-based poultry production systems. Considerations of poultry welfare standards provided through the specific system are also discussed. Production topics such as poultry genetics, outdoor access and pasture management are presented together with potential problems. Finally, various aspects of sustainability are analysed to estimate the environmental, economical and social benefits promoted by the pasture-based poultry production systems.