Influence of diet and rearing system on heavy pig performance, carcass and meat quality

Abstract

Identifying alternative dietary protein sources and new types of outdoor rearing techniques that enhance animal welfare, thus optimising costs and production performance, are among the main objectives of nutritionists and breeders. The aim of this study was to compare two types of rations where pea and potato concentrate completely substituted soybean in intensively and extensively bred swine. Forty Large White × Duroc piglets weighing about 40 kg were divided into 4 groups of 10 sex-and weightmatched individuals: Indoor rearing + Control diet, Indoor rearing + Experimental diet, Outdoor rearing + Control diet, Outdoor rearing + Experimental diet. Different diets were formulated for the growing phase (40-100 kg) and the fattening period (100-slaughter); pigs, weighed individually every 40 days to estimate the average daily gain and feed conversion rate, were slaughtered when they reached the weight for Italian ham production. The following measurements were obtained: carcass weight, slaughtered yield, weight of lean cuts, pH 45 minutes and 24 hours post mortem. 40 semimembranosus muscle samples were analysed for colour parameters (L*, a* and b*), moisture, fat, protein and ash while the energy values were calculated. Semimembranosus intramuscular fat and ham backfat were analysed for fatty acid profile. Statistical analysis of performances data was conducted using design with repeated measures and the slaughterhouse, meat and fat composition data were subjected to ANOVA. The results show that soybean can be completely substituted with other protein crops. Rearing and slaughterhouse performances were not affected by the diet, whereas significant differences emerged with the rearing system. Diet composition significantly affected lean meat proportion (50.0 vs 48.2) and fat thickness of 3/4 Thoracic Vertebra (25.3 vs 28.3 mm), while the rearing system significantly affected all carcass quality measures. Some parameters were better in outdoorthan indoor-subjects. Meat colour was also significantly influenced by the rearing effect, being less light and yellow in the former subjects (L* 49.9 vs 37.3; b* 3.7 vs 2.3). Chemical analysis demonstrated that the meat of outdoor-reared subjects was leaner (1.96% vs 1.38% fat) and had a lower water content (72.8% vs 71.8%). The complete replacement of soybean is thus compatible with a strong characterization and an enhancement of the value of swine products. In addition, the rearing system can result in distinctive quality features, such as ham colour and fat content, allowing products from outdoor rearing to be clearly recognized from those obtained from intensive rearing.

Effects of a soybean-free diet supplied to Italian heavy pigs on fattening performance, and meat and dry-cured ham quality

“…Findings from the present experiment are only partially consistent with those reported by Trombetta et al (2009), who replaced soya bean with a mixture of field pea and potato protein (the latter included at concentrations similar to our own) and found a reduction in the lean meat yield measured using a Fat-o-Meater. Meat, fat and dry-cured ham quality Table 4 shows the main qualitative parameters of meat (color, pH values and water holding capacity) and the chemical composition (protein, fat and ash content) of the Longissimus dorsi muscle; no significant differences were found between the groups.…”

“…Potato protein and corn gluten feed are mainly used in growing and fattening pigs receiving soybean-free diets to meet the protein and amino acid requirements (Sundrum et al, 2000;Trombetta et al, 2009). Findings from the present experiment are only partially consistent with those reported by Trombetta et al (2009), who replaced soya bean with a mixture of field pea and potato protein (the latter included at concentrations similar to our own) and found a reduction in the lean meat yield measured using a Fat-o-Meater.…”

“…The mixture of alternative ingredients (sunflower meal, corn gluten feed, faba beans, dehydrated alfalfa meal and potato protein), each included at a low percentage in the diets fed to heavy pig, did not affect (P>0.05) any of the production parameters (BW, ADG, FCR) or carcass traits (dressing out, lean meat yield, lean and fat cuts) studied (Tables 2 and 3). With respect to fattening performance, they were within the standard values for Italian heavy pigs (Mordenti et al, 1994;Sardi et al, 2006;Martelli et al, 2005;Trombetta et al, 2009) mixture of non-conventional protein sources similar to that used in the present experiment, led us to address separately the possible role of each single ingredient on growth and carcass parameters. However, the existence of positive or negative associative effects between ingredients cannot be ruled out.…”

“…Furthermore, available information mainly refers to the outcomes of applying extensive rearing systems and/or the organic method (Sundrum et al, 2000;Hoffman et al, 2003;Olsson et al, 2003;Millet et al, 2004;Trombetta et al, 2009), in which the use of alternative protein source interacts with rearing conditions influencing the final outcomes.…”

Effect of sire breed and rearing system on growth, carcass composition and meat traits of Cinta Senese crossbred pigs

“…Literature is controversial on the influence of alternative housing system on intramuscular fat content, as reviewed by Millet et al (2005). For instance, outdoor rearing, in respect to the indoor one, determined lower IMF content (Enfält et al, 1997;Gentry et al, 2002); or similar values (Van der Wal et al, 1993;Lebret et al, 2002); or higher IMF content (Lebret et al, 2006(Lebret et al, , 2011Trombetta et al, 2009). However, in the present trial, even if the three fat compartments (subcutaneous, intermuscular and Cinta Senese crossbred pigs performance intramuscular) exhibited analogous behaviour in relation to the rearing system, with a tendency to general higher adiposity for indoor housed pigs, it is noteworthy that only at the muscular level the difference became significant, confirming the high sensibility of this depot to environmental manipulation (Lebret et al, 2011) The genetic effect appears more important and affected in similar way both muscles.…”