Interactions between lipid source and vitamin A on broiler performance, blood parameters, fat and protein deposition rate, and bone development.

A total of 2622 male broilers were distributed in a 2 × 5 factorial design, using 2 lipid sources (soybean oil and palm fat), 5 levels of vitamin A supplementation (0, 3,000, 6,000, 12,000, and 24,000 IU kg-1), with 10 replicates, and also 1 control diet (CD) for each lipid source used (7 replicates), each experimental unit being composed of 23 birds. During the first 21 d (how were the birds fed) and from 22 to 42 d of age, a redistribution of the treatments was carried out in a 2 × 2 × 5 factorial design: half of the repetitions of each treatment received the diet of the initial treatment, and the others received the CD with its type of lipid source. In the phase from 1 to 21 d of age, the effect of lipid source on feed intake (FI) and feed conversion ratio (FCR), and the effect of vitamin supplementation on FI and weight gain (WG) were observed, with a quadratic response for both variables. At 42 d of age, the lipid source and vitamin A level influenced the FI, whereas the WG and FCR showed interactions between period and the level of vitamin A supplementation. Neither lipid source resulted in blood parameters out of the typical pattern for birds, and the same was observed in relation to dietary vitamin A supplementation. From 1 to 21 d of age, a vitamin A supplementation of 15,585 IU kg-1 was estimated, and at 42 d, 15,527 IU kg-1 and 15,148 IU kg -1 were estimated for the periods 1 to 21 d and 1 to 42 d, respectively.

Balanço eletrolítico da dieta e desempenho de frangos em condições naturais de estresse calórico / Electrolyte balance of diets under performance of broiler in naturals conditions of heat stress

Avaliou-se o efeito da suplementação de eletrólitos sobre o desempenho de frangos, utilizando bicarbonato de sódio (NaHCO3) e cloreto de potássio (KCl) para ajuste do balanço eletrolítico da dieta (BED) com duas porcentagens de proteína bruta (PB). Utilizaram-se 800 frangos machos, alojados em 20 boxes, distribuídos em delineamento inteiramente ao acaso, com quatro tratamentos, cinco repetições e 40 aves por unidade experimental. Os tratamentos foram: dieta basal; dieta sem redução de PB suplementada com eletrólitos para ajuste do BED para 250mEq/kg; dieta com redução de PB, sem suplementação de eletrólitos; e dieta com redução de PB, com eletrólitos para ajuste do BED para 250mEq/kg. Foram avaliados: consumo da dieta, peso final, ganho de peso, ganho de peso médio diário, conversão alimentar e calórica e eficiência de utilização de nitrogênio e lisina nas fases de sete a 21 e de sete a 42 dias. Não se observaram diferenças (P>0,05) no consumo da dieta. A correção do BED com menor teor de PB melhorou (P<0,05) o peso final, na fase inicial. Houve piora (P<0,05) no ganho de peso e na conversão alimentar nas duas fases. A redução de três pontos percentuais na PB da dieta piorou o desempenho dos frangos.

The effect of the supplementation of electrolytes on de performance of broilers using sodium bicarbonate (NaHCO3) and potassium chloride (KC1) to adjust the electrolytic balance of the diet (BED) with two percentages of raw protein (PB) was studied. 800 male broiler chickens, housed in 20 boxes, distributed in random lineation, with four treatments, five repetitions and 40 birds per experimental unit were used. The treatments were: base diet; diet with no reduction of PB supplemented with electrolytes to adjust BED to 250mEq/kg; diet with a reduction of PB, with no electrolyte supplementation; and diet with the reduction of PB, with electrolytes to adjust the BED to 250mEq/kg. What was evaluated was: diet consumption, final weight, weight gain, average daily weight gain, food conversion and caloric efficiency of the use of nitrogen and lysine in phases from 7 to 21 and 7 to 42 days. No differences were observed (P>0.05) in diet consumption. The correlation of BED with the lower percentage of PB improved (P<0.05) the final weight in the initial phase. Weight gain and food conversion worsened (P<0.05) in both phases. The reduction of three percentage points in the PB in the diet worsened the broiler chicken's performance.