Effects of fasting prior to slaughter on technological and sensory properties of the loin muscle (M. longissimus dorsi) of pigs

Cut yield and meat quality of brown eggshell laying hens housed in an alternative system and submitted to different feeding volumes

The aim was to evaluate the effect of different feeding volumes on the cut yield and meat quality of brown eggshell laying hens strain Embrapa 051 (E051) during the laying cycle, reared in an alternative system and slaughtered at 73 weeks, with reference to the lineage Lohmann Brown (LB). 600 hens E051 and 200 hens LB were used in an entirely randomized experimental design totalizing 5 replicates with 40 birds each. The treatments were: Control (LB fed with 100% of their dietary requirements), E051 fed with 93% of the control diet, E051 fed with 100% of the control diet, and E051 fed with 107% of the control diet. Birds were supplemented daily with 30g of ground grasses. Different feeding volumes did not alter the physicochemical quality of the meat and the cut yield. Body and cold carcass weight were greater in the E051 fed with 107% of the reference feed compared to the LB or the E051 fed with 7% less than the control diet. Yellow color intensity was greater in the E051 than in LB. The results demonstrated that, at the end of their productive cycle, the E051 without a restricted diet presents good carcass characteristics and potential for industrialized development.

Effects of slaughter weight and growth rate on the longissimus muscle metabolic characteristics, and pork sensory quality in pigs of two sexes

A total of 119 pigs were used to investigate the effect of slaughter weight (107, 115, and 125 kg), growth rate (fast vs. slow), and sex (barrows vs. gilts) on the longissimus muscle biochemical and sensory traits. Increasing slaughter weight to 125 kg resulted in greater postmortem activity of calpastatin (P = 0.01), lactate dehydrogenase (P = 0.01), and citrate synthase (P = 0.02). Pork toughness and juiciness at 6 d were affected by the interaction slaughter weight × growth rate × sex, with pork being tougher (P = 0.04) and juicer (P = 0.03) in slow-growing gilts slaughtered at 125 and 115 kg, respectively. Flavour was scored higher (P = 0.03) in pork from gilts than from barrows. Overall, based on the slight and likely undetectable differences by the average consumer in the meat sensory traits, it can be concluded that slaughter weight can be increased to 125 kg without appreciable effect on the sensory properties.

Effects of aging on characteristics of breast meat from free-range broiler hens at 12 or 70 weeks of age

We evaluated the effect of broiler age and aging process on the meat characteristics of breast fillets from female free-range broilers slaughtered at 12 weeks of age (Wk12) and 70 weeks of age (Wk70). We used breast meat from female ISA Label (n = 60) broilers. Ten samples of each broiler age were aged in an incubator (2°C ± 0.5°C) for 3 and 7 days. Ten samples for each broiler age were analysed 4 h post-slaughter (Control group). Compared with breast meat from Wk12, breast meat from Wk70 showed higher shear force (30.52 N vs 27.19; P = 0.0322) and total collagen (4.33 g/kg vs 3.77 g/kg; P = 0.0149), which were reduced during aging to 15.49 N and 3.92 mg/100 g, respectively. The aging process did not affect the lipid oxidation of breast meat from Wk70. After aging for 3 days, breast meat from Wk70 had similar protein and fat contents to those of meat from Wk12 (21.29% and 1.04%, on average, respectively). Breast meat from Wk70 also showed lower concentrations of docosahexaenoic (0.32% vs 0.65%; P < 0.0001) and eicosapentaenoic (0.01% vs 0.12%; P < 0.0001) fatty acids than meat from Wk12. The use of free-range hen meat is beneficial to the industry because of the lower storage and cooking losses, which may influence the final yield, besides its lower polyunsaturated fatty acid concentration, which makes it less vulnerable to rancidification. Aging for at least 3 days at 2°C is satisfactory to promote the tenderisation of meat from free-range broiler hens.

Jejum alimentar e qualidade da carne de frango de corte tipo caipira

ResumoObjetivou-se avaliar as características de qualidade da carne de frango de corte tipo caipira em diferentes tempos de jejum alimentar. Aves, machos, da linhagem “pesadão vermelho”, criadas até 85 dias de idade em sistema semiextensivo, foram submetidas aos tempos de zero, três, seis, nove e 12 horas de jejum alimentar. Obteve-se o peso vivo, peso da carcaça, o rendimento de carcaça fria, o peso do trato gastrintestinal das aves. Foram avaliados o pH24h, a luminosidade (L*), o teor de vermelho (a*), o teor de amarelo (b*), a capacidade de retenção de água, a perda de peso por cocção e a força de cisalhamento na carne do peito, da coxa e da sobrecoxa. Menor valor de rendimento de carcaça foi observado no tempo zero hora (74,54%), e o maior (82,43%) às nove horas de jejum alimentar. Maior peso para o trato gastrintestinal (540,8g) foi observado no tempo zero e o menor (229,33g) às 12 horas de jejum alimentar. Não foi observado efeito dos diferentes tempos de jejum alimentar nas características de qualidade da carne das aves. Houve diferença no pH24h, na luminosidade (L*), no teor de vermelho (a*), no teor de amarelo (b*) e na capacidade de retenção de água quando se comparou os cortes da carne do peito, da coxa e da sobrecoxa das aves de corte tipo caipira. Recomendam-se os períodos de jejum de nove ou 12 horas, nos quais houve maior rendimento de carcaça fria.

Selective mobilization of fatty acids in adipose tissue of heavy pigs

The mobilization of fatty acids during food deprivation is a selective process studied in different species (humans, rodents, birds, viverrids). The aim of this work was to study the effect of fasting on selective mobilization in commercial pigs. A total of 16 barrows (Large White×Landrace (167 kg±12.5 kg live weight) were subdivided into two homogeneous groups, one subjected to 12 h and the other to 60 h of fasting (fasting time) before slaughtering. For each pig inner and outer backfat layer were sampled at slaughter and at ham trimming 24 h later (sampling time). Increasing the fasting time and the sampling time after slaughter caused an increase in the amount of free fatty acids in both layers. Therefore it can be argued that during fasting lipolysis is stimulated and remains active also after slaughtering. The factors that stimulate lipolysis determine a greater mobilization of unsaturated fatty acids than saturated ones. Thus fasting time may influence the suitability of pork for processing and conservation, since free fatty acids are more suitable for oxidation than the esterified ones.

Bayesian meta-analysis of the effect of fasting, transport and lairage times on four attributes of pork meat quality

Technological meat quality is a significant economic factor in pork production, and numerous publications have shown that it is strongly influenced both by genetic status and by rearing and slaughter conditions. The quality of meat is often described by meat pH at different times postmortem, as well as by color and drip loss. A meta-analysis based on a database built from 27 studies corresponding to a total of 6526 animals classified was carried out. The purpose of this meta-analysis was to study the effect of fasting, lairage and transport durations on four main attributes of the technological pork meat quality. A Bayesian hierarchical meta-regression approach was adopted. The results of our meta-analysis showed that fasting time had a significant effect on pH measured 24h post-mortem (pHu) and drip loss (DL) measured in longissimus muscle. While, lairage affected only the pHu in semimembranosus muscle. Interestingly, we found that DL was the lone attribute that was affected by transport time and its interaction with fasting time.