Nutrient oxidation in pork loin is influenced by feed supplementation and packing methods

Copper and zinc hydroxychloride cosupplementation improve growth performance and carcass and reduce diarrhea frequency in grower-finisher pigs

This study investigated copper (Cu) and zinc (Zn) hydroxychloride cosupplementation on the growth performance, diarrhea frequency, carcass, meat quality, and antioxidant activity in grower-finisher pigs. A total of 256 pigs were used from 70 to 154 days (d) of age, distributed in four treatments, with eight pigs in each pen and eight replications per treatment. Diets were provided to grower pigs from 70 to 112 days old and in the finisher, 112 to 154 days old. Copper was considered the low level at 100 mg Cu/kg and 90 mg Cu/kg, respectively, and 150 mg Cu/kg in both periods as high in the grower and finisher periods. In the grower and finisher period, zinc was cosupplemented in the diet at 80 mg Zn/kg and 70 mg Zn/kg, respectively. In the diets, T1 and T2 groups are the traditional inorganic sources for minerals (copper sulfate, CuSO₄; zinc oxide, ZnO) and T3 and T4 hydroxychloride sources (copper hydroxychloride, CHC, and zinc hydroxychloride, ZHC). The flavomycin was associated with treatments with low Cu content in the inclusion of 50 g/ton. The experimental design was in randomized blocks, the data were submitted to analysis of PROC MIXED in SAS, the PDIFF test analyzed the treatment effect. At the finisher period, pigs fed both minerals from hydroxychloride source had a higher BW 154 d, average daily gain (ADG) 70 to 154 d, the hot and cold carcass weight and frequency of normal feces than those fed 150 mg Cu/kg and Zn from a traditional inorganic source (P < 0.05). The animals fed low Cu levels of the sulfate source had a higher ADG 70 to 154 d than those fed high Cu levels of the same source (P < 0.05). Pigs fed 150 mg Cu/kg cosupplemented with Zn from a hydroxychloride source had the highest carcass length (P < 0.05). There was no difference among the treatments for meat quality (P > 0.05). Pigs fed 150 mg Cu/kg and Zn from a traditional inorganic source had a higher superoxide dismutase (SOD) activity than the other treatments (P < 0.05). Animals fed low Cu levels from hydroxychloride had a higher malondialdehyde (MDA) formation than those fed sulfate source, regardless of the Cu levels and those fed high Cu levels of hydroxychloride (P < 0.05). In conclusion, 150 mg Cu/kg as copper sulfate cosupplemented to zinc oxide in the diet of growing and finishing pigs impairs the growth performance, carcass and increases diarrhea frequency, and copper and zinc hydroxychloride cosupplementation improves these characteristics.

The Effect of PUFA-Rich Plant Oils and Bioactive Compounds Supplementation in Pig Diet on Color Parameters and Myoglobin Status in Long-Frozen Pork Meat

The study evaluated the effect of pig diet supplementation with rapeseed or linseed oil, and vitamin E or selenium, or both vitamin E and selenium on color parameters and myoglobin content of pork Semimembranosus muscle after long-term freezing storage during nine months. The influence of the type of the bioactive compounds added to pig diet on the content of myoglobin or oxymyoglobin, metmyoglobin and deoksymyoglobin in Semimembranosus m. was also assessed. The results indicate that the presence of oils rich in polyunsaturated fatty acids (PUFA) in pig diet improves the color of pork meat. Supplementation of dietary plant oils or dietary oils with antioxidants tended to increase significantly the concentration of oxymyoglobin and decrease the concentration of metmyoglobin in meat compared to the control group. The highest content of oxymyoglobin was observed in meat obtained from pigs fed diets with linseed oil. The best color scores (highest a* parameter) was noted for rapeseed oil group (with no addition of antioxidants). In conclusion, the addition of antioxidants to pigs’ forage supplemented with PUFA-rich oils is not recommended in order to improve color of long-term frozen pork.