High ambient temperature represents an increasingly frequent challenge for animal farming, especially for those animal species more susceptible to heat stress (HS), like the rabbit. The present research studied the impact of different ambient temperatures (T: 20 °C—Control vs. 28 °C—High) on the meat quality of two rabbit lines (L: Fat line, Lean line) obtained after 5 generations of divergent selection for total body fat content. After slaughter, the ground meat of 60 carcases (15 rabbits/treatment) was used for physicochemical and sensory quality evaluation. Overall, high T affected hind leg weight (p < 0.001), pHu (p = 0.001), and oxidative status (p = 0.004) during a shelf-life trial. High T increased meat haem-iron (p < 0.001), decreased lipids (p < 0.001), MUFA (p < 0.001), and PUFA classes (p < 0.001), and consequently, increased water content (p < 0.001). Regarding L effect, Fat line was richer in lipids (p < 0.001) and ash (p = 0.008), but less rich in water (p < 0.001) than Lean line. The content of all fatty acid (FA) classes was therefore significantly higher in Fat line meat (p < 0.001). It can be concluded that the two genotypes differed for proximate composition, haem-iron, FA, and amino acid profiles of carcase meat. High T increased meat pHu, water, haem-iron, and reduced polyunsaturated FA (PUFA) amount. At high T the meat of the Fat line showed higher TBARS, whereas Lean line had higher lysine content. Sensory analysis revealed that high T improved tenderness and extinguished onion off-flavour.

The present experiment was conducted to test the effect of a 4% defatted silkworm (Bombyx mori) pupae meal (SWM) incorporation into chickens’ diets at different growth phases on meat quality characteristics and sensory traits. Ninety ROSS 308 day-old male broiler chickens were randomly assigned to 3 dietary groups, with 5 replicated pens/diet: the first group received a control (C) diet throughout the growing period of 42 d, the second group received a diet with 4% SWM (SWM1) during the starter phase (1–10 d) and the C diet up to slaughter, whereas the third group was fed the C diet during the starter phase and 4% SWM during the grower and finisher phases (SWM2). Diets were isonitrogenous and isoenergy, and birds had free access to feed and water throughout the experimental trial. At 42 d of age, 15 chickens/treatment were slaughtered at a commercial abattoir. Fatty acid (FA) and amino acid (AA) profiles and contents of meat, as well as its oxidative status, were determined in both breast and leg meat cuts. Also, a descriptive sensory analysis was performed on breast meat by trained panelists. Results highlighted that the SWM2 treatment increased the n-3 proportion and content in both breast and leg meat, thereby improving the omega-6/omega-3 (n-6/n-3) ratio in both cuts (P < 0.001). However, the dietary treatment had no significant effect on the oxidative status of either breast or leg meat (P > 0.05). The SWM had a limited impact on overall sensory traits of breast meat, but it contributed to improve meat tenderness in SWM-fed chickens (P < 0.01). Furthermore, SWM1 meat exhibited higher juiciness (P < 0.05) and off flavor intensity (P < 0.05) compared to the control meat. Overall, the present experiment indicated that defatted SWM holds promise as an alternative ingredient in chicken rations, ensuring satisfactory meat quality. Furthermore, administering SWM during the grower-finisher phase demonstrated beneficial effects on meat healthiness, ultimately enhancing n-3 fatty acids content and reducing the n-6/n-3 ratio.

The present study was conducted to assess the effects of a 4% defatted silkworm (SWM-DEF) meal dietary incorporation into chickens’ diet at different growth stages on growth performances, carcass, and meat quality traits. A total of 90 Ross 308 one-day-old male broiler chickens were randomly allocated into 3 dietary groups of 5 replicated pens/diet (6 chickens/pen). One group was fed a standard soybean-based diet (C); group SWM1 consumed a starter diet (1–10 days of age) including 4% SWM-DEF and then the C diet up to slaughter (11–42 days of age); group SWM2 was fed with the C diet in the starter phase and the 4% SWM-DEF diet up to slaughter. Individual live weight and pen feed intake were determined at the end of each feeding phase: starter, grower, and finisher. Weight gain and FCR were then calculated. At 42 days of age, chickens were slaughtered and carcass traits determined. Leg and breast physico-chemical meat quality was also evaluated. Results confirmed that SWM-DEF could be a possible alternative feed source for chickens since growth performance, carcass, and meat physical traits were overall comparable in the three treatment groups. The feeding stage seemed to play a relevant impact on the sole meat protein content (SWM1 < SMW2 and C; p < 0.001). Concluding, the results available to date indicate that 4% SWM-DEF can be provided to chickens in different growth phases, and the choice of the inclusion period is more an industrial cost-benefit evaluation. From the scientific point of view, however, an administration in the grower-finisher phase rather than in the starter one provided the best meat nutritional quality. Further investigations should focus on the impact on meat fatty acids profile and sensory traits, which are of utmost importance for consumers.

The effects of heat stress and feed restriction were evaluated on a total of 180 weaned rabbits divided into three experimental groups (60 animals/group): 2 groups were fed ad libitum and reared under different temperatures (20 °C – 20AD and 30 °C – 30AD), while a third group was housed under controlled temperature (20 °C) but pair-fed to 30AD rabbits, thus feed restricted (20FR). During the trial, both 30AD and 20FR groups exhibited reduced growth performance, including body weight and daily weight gain (both, P < 0.001), although feed conversion ratio improved (P = 0.016). The reference carcasses of 20FR and 30AD rabbits were lighter and leaner (both, P < 0.001) than that of 20AD rabbits, while the slaughter yield decreased only in 20FR rabbits (P = 0.001). Regarding meat physical traits, 20FR rabbits exhibited the highest pHu (P < 0.001) and the lowest total losses (P < 0.001), whereas the meat-to-bone ratio decreased in both 20FR and 30AD groups (P = 0.007). As for meat proximate composition, protein and lipid contents were lower (P = 0.008 and P = 0.0002, respectively) in 20FR and 30AD rabbits, while water content was greater (P < 0.001) compared to 20AD rabbits. At the lipid level, higher TBARS (P = 0.001) were found in both 20FR and 30AD groups. The 20FR and 30AD groups showed some differences in their carcass and meat quality traits, however the majority of changes induced by chronic heat stress were mostly attributed to the reduced feed intake.