Effects of organic Selenium- and Chromium-Enriched Diets on performance, carcass characteristics, lipid profile and fat quality of finishing pigs in different weight ranges.

An experiment was conducted to evaluate the fatty acid profile of subcutaneous fat from barrowS of same genetic lineage supplemented with organic chromium and selenium initiated in different weight ranges in the finishing phase using 24 carcasses. Three different diets were used that represent the time when supplementation starts: control - without the inclusion of organic Cr and Se; CrSe70 - control with 500 g ton-1 of organic Cr and Se of 70 to 130 kg in body weight; and CrSe100 - control with inclusion of 500 g ton-1 of organic Cr and Se from 100 kg to 130 kg body weight. Performance, carcass characteristics, and lipid profile were evaluated. The data were submitted to analysis of variance, and with significant differences (p<0.05), the means were compared using the Tukey test. From 70 to 100 kg, control and CrSe70 animals consumed less feed than CrSe100. From 100 kg body weight, it reduced the C20:5n3 and C24:1n9 acids and increased the activity of the Δ-6 desaturase, elongase, Δ-5 desaturase enzymes in the supplemented animals. The moment when supplementation starts of organic chromium and selenium does not improve the performance and carcass characteristics, does not change the fatty acid profile, and does not improve the quality of the fat.

Combination of phytase and citric acid, but not phytase alone, ensures regular rates of growth and bone mineralization in quails under severe phosphorus restriction.

An experiment was conducted to evaluate the effects of phytase (PHY), alone or in combination with citric acid (CA), on growing Japanese quails under moderate and severe phosphorus (P) restriction. For this, 504 one-day-old female quails were distributed in a completely randomised design with seven treatments and six replications. Treatments consisted of the following diets: (a) positive control (PC): formulated according to quails nutritional requirements; (b) negative control 40% (NC40 ): PC with 40% less aP; (c) NC40 +PHY; (d) NC40 +PHY+CA; (e) negative control 65% (NC65 ): PC with 65% less aP; (f) NC65 +PHY; (g) NC65 +PHY+CA. Phytase and CA were included at 300 FTU/kg and 40 g/kg, respectively. Performance, bone mineralization and plasma mineral concentration were evaluated at day 35; calcium (Ca) and P metabolism, between days 36 and 39. No significant differences in performance, plasma Ca and P were detected between quails fed PC or NC40 ; however, NC40 decreased tibia ash (p < 0.01). Treatment NC65 impaired daily weight gain (p = 0.01), tibia ash (p < 0.01), and tibia optical densitometry (p = 0.03), as well as modified plasma Ca (p < 0.01) and P (p = 0.03) concentrations when compared to PC. Both NC40 and NC65 reduced P excretion (p < 0.01). Phytase alone restored tibia ash of NC40 quails to regular rates. Nevertheless, only PHY and CA combined returned plasma P, tibia ash, tibia optical densitometry, and daily weight gain of quails fed NC65 to similar values as those observed in PC. In conclusion, PHY alone suppresses the negative effects of moderate P restriction in growing Japanese quails, but fails in this task under severe P restriction. In such a situation, only the combination of PHY and CA ensures regular rates of growth and bone mineralization. This concept should be better explored by producers in order to take full advantage of the reduction in P excretion achieved by lowering dietary P concentrations.