Effect of Genotype, Gender, and Feed Restriction on Slaughter Results and Meat Quality of Broiler Chickens

Slaughter results and meat quality were evaluated in 768 broilers according to genotype (standard breast yield vs. high breast yield), gender, and feeding systems (ad libitum vs. feed restriction from 13 to 21 d of age). Standard-yield chickens had higher carcass weights (2358 g vs. 2319 g; P < 0.001) and hind legs proportion (31.1% vs. 30.6%; P < 0.01), and lower dressing out percentage (73.6% vs. 74.0%; P < 0.01) compared to high-yield birds, besides lower meat L* index (45.3 vs. 46.2; P < 0.05), higher final pH (5.89 vs. 5.85; P < 0.05) and thawing losses (10.5% vs. 9.43%; P < 0.05). Males showed higher carcass weight (+24%), dressing percentage (+0.7%), and hind leg yield (+4%) (P < 0.001) than females. Restricted birds had lower carcass weight (\u20132%; P < 0.001) and dressing percentage (-0.3%) (P < 0.05) than those always fed ad libitum. As what concerns meat quality, gender and feeding system aff ected only meat final pH, lower in ad libitum group than in restricted one and in females than males. In conclusions, slaughter results and carcass traits changed especially with genotype and gender, coherently with slaughter weight whereas meat quality was mostly affected by genotype

Effect of stocking density of fish on water quality and growth performance of European Carp and leafy vegetables in a low-tech aquaponic system

Aquaponics (AP) is a semi-closed system of food production that combines aquaculture and hydroponics and represents a new agricultural system integrating producers and consumers. The aim of this study was to test the effect of stocking densities (APL, 2.5 kg m-3; APH, 4.6 kg m-3) on water quality, growth performance of the European Carp (Cyprinus carpio L.), and yield of leafy vegetables (catalogna, lettuce, and Swiss Chard) in a low-technology AP pilot system compared to a hydroponic cultivation. The AP daily consumption of water due to evapotranspiration was not different among treatments with an average value of 8.2 L d-1, equal to 1.37% of the total water content of the system. Dissolved oxygen was significantly (p < 0.05) different among treatments with the lowest median value recorded with the highest stocking density of fish (5.6 mg L-1) and the highest median value in the hydroponic control (8.7 mg L-1). Marketable yield of the vegetables was significantly different among treatments with the highest production in the hydroponic control for catalogna (1.2 kg m-2) and in the APL treatment for Swiss Chard (5.3 kg m-2). The yield of lettuce did not differ significantly between hydroponic control and APL system (4.0 kg m-2 on average). The lowest production of vegetables was obtained in the APH system. The final weight (515 g vs. 413 g for APL and APH, respectively), specific growth rate (0.79% d-1 vs. 0.68% d-1), and feed conversion (1.55 vs. 1.86) of European Carp decreased when stocking density increased, whereas total yield of biomass was higher in the APH system (4.45 kg m-3 vs. 6.88 kg m-3). A low mortality (3% on average) was observed in both AP treatments. Overall, the results showed that a low initial stocking density at 2.5 kg m-3 improved the production of European Carp and of leafy vegetables by maintaining a better water quality in the tested AP system

Influence of group housing, lactation system and floor type on performance and injuries in rabbit does

To evaluate the effect of group housing, lactation system, and floor type, 40 crossbred multiparous pregnant rabbit does were transferred to individual pens (0.5 m x 1.0 m); 8 does were kept individually during all the trial (I; n=8); the other 32 does were kept in 8 collective pens (2.0 m x 1.0 m, by joining 4 individual pens) in stable groups of 4 individuals (G; n=8) from 8 d until 2 d before kindling and from 2 d until 33 d after kindling. Half pens had wire net floor covered with plastic mats (W; n=8) and the other half plastic slatted floor (P; n=8). Within G does, in half pens (n=4) each doe nursed its own litter (fixed lactation, F); in the remaining half, each doe randomly nursed the litters of the group (random lactation, R). Doe performance at kindling and during lactation, litter performance from standardization until weaning (33 d), and skin injuries on G does (5, 12, 19, 26 and 34 d after kindling) were controlled. The effect of the housing system on performance was tested by PROC GLM of SAS. Within G does, the effect of the lactation system and floor type was evaluated by PROC MIXED (pen as random effect); the injury frequency was analysed by PROC FREQ according to observation day, lactation system, and floor type. Housing system did not affect doe kindling or lactation performance; litter weight at standardization was higher for G than I does (680 vs 619 g, P<0.05), but differences disappeared at weaning. The lactation system showed some residual effects when controlled lactation finished, nests were opened, and kits free of moving. In fact, from 19 to 33 d after kindling, does and litters had higher feed intake (679 g/d vs 602 g/d; P<0.05) and, at 33 d, kits were heavier (775 vs 748 g, P<0.05) in R than in F pens. Floor type (W vs P pens) affected milk production (244 vs 225 g/d; P=0.06), and kit weight at the end of controlled lactation (301 vs 290 g; P<0.05), without residual effects at weaning. The injury frequency changed after the group formation: 34% at 5 d, 47% at 12 d, 13% at 19 and 26 d, and 10% at 34 d of lactation (P<0.05). In conclusion, under our conditions, group housing did not negatively affect doe performance; lactation system and floor type had minor effects; aggressiveness among does was evident after group formation during early lactation but decreased in the late lactation. Further recordings on more reproductive cycles would be necessary to confirm the present results

Effects of the feeding system on performance and myopathy occurrence in two broiler chicken genotypes

To evaluate whether performance and myopathy occurrence differed according to genotype (Cobb 500 vs. Ross 308) and feeding system (AL: ad libitum vs. ER: early restricted from 13 to 23 d of age, vs. LR: late restricted from 27 to 37 d; restriction rate: 80% of ad libitum), 828 day- old male chicks were assigned to 6 groups (2 x 3 arrangement), housed in 36 pens, and controlled for: individual live weight (weekly) and pen feed intake (daily) until slaughter (48 d); white striping and wooden breast occurrence at slaughter. Individual data were analysed by PROC MIXED of SAS (fixed effects: feeding system, genotype, and interaction; random effect: pen); pen feed intake and myopathy occurrence were analysed by PROC GLM and CATMOD, respectively. The feeding system affected performance: at the end of the first period (1-22 d), ER chickens showed lower weight gain (40.5 g/d vs. 47.8 g/d and 48.0 g/d), feed intake (50.8 g/d vs 61.0 g/d and 60.2 g/d) and weight (903 g vs 1056 g and 1059 g) than AL and LR broilers (P<0.001); at the end of the second period (23-48 d), ER chickens showed higher weight gain (98.3 g/d vs 93.6 g/d and 90.2 g/d) and feed intake (182 g/d vs. 177 g/d and 171 g/d) compared to AL and LR chickens (P<0.001). Final live weight was the highest in AL group, intermediate in ER group, and the lowest in the LR one (3482 g, 3454 g, and 3399 g; P<0.01). Feed conversion in the whole period did not change with the feeding system. At gross examination, white striping occurrence changed from 77.8% to 67.1%, and 81.7% in AL, ER and LR broilers (p<0.10). Differences between genotypes were evident from the first day and, at the end of the trial, weight gain (74.3 g/d vs 70.1 g/d), feed intake (126 g/d vs 114 g/d), feed conversion (1.69 vs 1.64), and live weight (3548 g vs. 3342 g) were higher in the Ross than in the Cobb chickens (P<0.001). At slaughter, the rate of white-striped breasts was similar (on average 75.5%), but the occurrence of severely white-striped breasts was higher in the Ross than in the Cobb chickens (25.9% vs. 7.41%; P<0.001). Wooden breast occurrence (on average 5.1%) did not change with the feeding system or the genotype. In conclusion, under our conditions, a late feed restriction did not permit to recover performance at the end of the trial nor to control white striping occurrence. Moreover, the genotype affected growth rate and white striping degree: the highest the growth rate, the highest the severity of white striping

Performance, health and slaughter traits of group-housed rabbits submitted to different time-based feed restriction programs

Growth performance, health and slaughter traits were measured in 320 crossbreed rabbits housed in 40 open-top pens (8 rabbits/pen) from weaning to slaughter (34–70 d of age) to evaluate the effects of the different feeding programs: AL, ad libitum feeding; DF, daylight access to feed with fast and complete refeeding; NF, night access to feed with fast and complete refeeding; NS, night access to feed with slow and complete refeeding; NI, night access to feed with very slow and incomplete refeeding. In restricted rabbits, the feeding time decreased from 14 to 9 h/d during the 1st week, remained stable (8 h/d) during the 2nd week, and increased from the beginning of the 3rd week according to three refeeding programs: i) fast until ad libitum (+4 h/d until 24 h/d); ii) slow until ad libitum (+1 h/d until 24 h/d); iii) very slow and still restricted until the end of fattening (+30 min/d until 12 h/d). In the restricted rabbits, feed intake (-3.7%) and feed conversion (–5.6%) were lower compared to AL ones (P<0.001) with the minimum values in the NI group. Diet digestibility increased in the restricted groups compared to AL and in the NI group compared to other restricted groups. Mortality was lower in AL rabbits compared to restricted ones (1.6% vs. 9.0% on average; P=0.04), whereas morbidity and health risk index did not change. Slaughter weight (2608 g), dressing percentage (60.2%), and carcass muscularity were not affected by the feeding program. In conclusion, the NI program represented the best strategy to optimize feed efficiency without impairing growth, slaughter results and carcass traits in growing rabbits. The tested feed restriction programs did not succeed in enhancing rabbit health

Dietary supplementation of butyrate in growing rabbits

The UE restrictions imposed on the antibiotic utilization in animal husbandry have increased the interest on alternative additives capable of improving animal digestive health. Among the numerous tested products, short chain fatty acids stimulated intestinal mucus production at different level and intestinal cells proliferation in rats (Meslin et al., 2001; Moreau et al., 2003). Short and medium chain fatty acids could also modulate intestinal microflora: in rabbits, the antimicrobial activity of caprilic and capric acids was proved on various strains of Clostridium perfringens and Escherichia coli (Marounek et al., 2002). The present trial aimed to evaluate the effect of butyrate inclusion and level on growth performance, health status, digestive physiology and slaughter traits in growing rabbits

Recommendations and guidelines for applied nutrition experiments in rabbits

[EN] The aim of this paper was to draw up a set of recommendations for applied nutrition and feeding trials with rabbits, in relation to certain aspects such as determining the nutritive value of raw materials or diets in growing or reproducing animals, studying digestive physiology and obtaining growth and reproduction parameters. We deal first with animals, size of the sample, housing conditions, diets, handling, measurements, and the data analyses relevant to the design of the experiment are described. Secondly, we give a list of recommended items and include some comments.This study was partly supported by the EUROPEAN COMMISSION (ERAFE program and the COST 848 Action).Fernández-Carmona, J.; Blas, E.; Pascual Amorós, JJ.; Maertens, L.; Gidenne, T.; Xiccato, G.; García, J. (2005). Recommendations and guidelines for applied nutrition experiments in rabbits. World Rabbit Science. 13. doi:10.4995/wrs.2005.516SWORD1

Nitrogen excretion in dairy cow, beef and veal cattle, pig, and rabbit farms in Northern Italy

Reference values for N excretion of different livestock production systems are required for the application of the Nitrate Directive (91/676/EC). A survey aimed to estimate N excretion from on-farm measurements of feed consumption and performance of dairy cows (104 herds, 9,984 cows), growing cattle (40 farms, 40,157 young bulls), veal calves (34 farms, 49,206 calves), growing pigs (39 farms, 161,278 pigs) and rabbits (54 farms, 65,664 reproducing does) was conducted in Veneto from 2002 to 2003. N excretion was computed as the difference between N consumption and N retained in animal products. Dairy cow yielded 8,366 ± 1,646 kg/year of milk, consumed 6,600 ± 928 kg/year of DM, containing 2.45 ± 0.2 % DM of N, and excreted 116 ± 25 kg of N/year. No significant correlation was found between milk yield and N excretion, but the correlation between dietary N concentration and N excretion was significant (r=0.66). For growing cattle, the following mean values were achieved: daily gain 1.25 ± 0.19 kg/d; feed conversion ratio 6.9 ± 0.9 kg of DM/kg, rounds/year 1.66 ± 0.38. Nitrogen consumed, retained and excreted were, respectively, 68.7 ± 5.4, 11.4 ± 1.9 and 57.3 ± 4.9 kg/place/year. For veal calves, N consumed was 24.1 ± 1.9 kg/place/year, 12.1 ± 0.8 kg of which were retained in the body and 12.0 ± 1.5 kg were excreted. For heavy pig production, N consumed, per place and per year, averaged 19.0 ± 1.9 kg, N retained was 5.2 ± 0.5 kg and N excreted was 13.8 ± 0.4 kg. In the close-cycle rabbit farms, the doe and the relative growing rabbits (43 sold per year) consumed 11.2 ± 2.2 kg, retained 3.8 ± 0.7 kg and excreted 7.4 ± 1.5 kg N/doe/year. Nitrogen excretion estimated in this work can be considered as representative of some of the main animal production systems of the North-East of Italy. These values should not be considered as fixed, otherwise the implementation of the various strategies to reduce N excretion would not be possible. They should be considered as guidelines in the assistance both to public institutions and private enterprises in the evaluation of N excretion at farm level, favouring a more accurate quantification of the excretions, an increase of N retention efficiency and a better knowledge of the requirements of agricultural land. Moreover, a major extension of the agricultural land to be fertilised with manure should be promoted

Effect of pre-slaughter conditions in European sea bass (Dicentrarchus labrax)

The increasing attention towards animal welfare also concerns aquaculture species, with special regards to husbandry and slaughter conditions. Both the extent and the duration of stressful events especially before slaughter may affect post-mortem evolution of biochemical processes and product shelf-life (Pottinger, 2001; Zampacavallo et al., 2003). The present work aimed to evaluate the effects of preslaughter conditions in European sea bass according to i) stocking density and ii) time spent in confinement tanks after catch and before slaughter on physiological indicators of stress and meat quality during storage