Two experiments were carried out to evaluate, respectively, nitrogen balance (NB) and the productive performance of 31-to-50-day-old rabbits subjected to different levels of lysine and methionine+cystine (met+cys). Seventy-five animals were randomly distributed in 5 × 3 blocks (five levels of lysine: 5.5, 6.5, 7.5, 8.5 and 9.5 g/kg combined with three levels of met+cys: 5.0, 6.0 and 7.0 g/kg), with 15 treatments and five replications for the NB assay. The assay lasted 14 days: 10 days for acclimatization and four days for feces and urine collection. Increasing met+cys levels had a quadratic effect on the nitrogen excreted in urine (NU): the lowest excretion was found at the dietary level of 5.9 g/kg met+cys. Increasing lysine levels also affected NU and nitrogen retained daily (NR): the lowest NU was obtained at the dietary level of 7.28 g/kg lysine, and maximum NR was found at 7.24 g/kg lysine. Increases in met+cys levels in the diets affected neither performance nor carcass characteristics of rabbits up to 50 days of age. On the other hand, body weight at 50 days, daily weight gain and feed conversion of rabbits slaughtered at 50 days had a quadratic effect as the lysine levels increased. The best results were found at 7.5, 7.38 and 7.36 g/kg lysine. Lysine and met+cys levels of 7.4 and 5.0 g/kg in the diet are recommended for 31-to-50-day-old rabbits.

Conduziram-se experimentos para determinar a digestibilidade da polpa cítrica desidratada (PCD) e avaliá-la na alimentação de coelhos. Para o ensaio de digestibilidade utilizaram-se 30 coelhos recebendo duas dietas: uma referência e outra com substituição de 20% da primeira por PCD. O ensaio teve duração de dez dias para adaptação mais quatro para coleta de fezes. Os coeficientes de digestibilidade e os nutrientes digestíveis para MS, PB, FDN, FDA e EB da PCD foram respectivamente: 83,75 e 76,04%; 70,12 e 5,03%; 40,14 e 9,52%; 68,98 e 15,09%; e 81,48% e 3394 kcalED kg-1 MS. Para o desempenho utilizaram-se 120 coelhos recebendo dietas com diferentes níveis de PCD (0, 20, 40, 60, 80 e 100%) substituindo o milho. Observou-se redução linear (p < 0,01) para o consumo de ração e ganho de peso diário, peso vivo aos 50 e 70 dias e rendimento de carcaça com o aumento gradativo de PCD. Efeitos quadráticos (p < 0,01) sobre a conversão alimentar dos 32 aos 50 e 32 aos 70 dias de idade provocaram melhores valores com 42,74 e 44,40% de PCD, respectivamente. PCD a 20% não afetou (p > 0,05) nenhuma característica de desempenho quando comparada à dieta controle. Conclui-se: a PCD pode substituir o milho até 20% nas dietas de coelhos.

Several experiments were conducted to determine the digestibility of dehydrated citrus pulp (DCP) and evaluate its effect on rabbit feed. Digestibility assay comprised 30 rabbits fed on two diets: a reference diet and a diet in which 20% consisted of DCP. The digestibility assay comprised 10 days for adaptation and four days for feces collection. The digestibility coefficient and digestible nutrient rates for DM, CP, NDF, ADF, and CE of DCP were respectively 83.75 and 76.04%; 70.12 and 5.03%; 40.14 and 9.52%; 68.98 and 15.09%; and 81.48% and 3394 kcalDE kg-1 DM. Performance assay consisted of 120 growing rabbits receiving diets with six DCP levels (0, 20, 40, 60, 80 and 100%) to replace corn. Linear decrease (p < 0.01) in daily feed intake and weight gain, live weight after 50 and 70 days and carcass yield with gradual DCP increase, were reported. Quadratic effect (p < 0.01) on the feed conversion from 32 to 50 and from 32 to 70 days old produced better DCP rates, respectively 42.74% and 44.40%. DCP 20% failed to affect (p > 0.05) any performance characteristic when compared to that in control. Results show that DCP in the rabbit's diet may replace up to 20% of corn.

Two experiments were carried out in order to estimate the nutritional value and the performance of growing rabbits fed different levels of pearl millet (ADR 7010). In the digestibility trial, nutritional values of pearl millet were determined in 22 45-day-old New Zealand White rabbits, allotted in a completely randomized design, subjected to two treatments - a reference diet and a test diet with 70% of its volume composed of reference diet and 30% of pearl millet - and 11 replications. The apparent digestibility values of dry matter, crude protein, neutral detergent fiber and gross energy of the pearl millet were 88.7, 85.4, 24.4 and 75.0%, respectively. In the performance trial, 120 32-day-old New Zealand White rabbits were used. Rabbits were allotted in a completely randomized design and subjected to six treatments, with 10 replications and two animals for each experimental unit. The diets were formulated with increasing levels of pearl millet (20, 40, 60, 80 and 100%), substituting the corn in the reference diet, according to the digestible energy. No differences were observed in daily feed intake, daily weight gain, feed conversion, carcass traits and feed cost per kilogram of rabbit. Regardless of the amount of corn substituted, pearl can replace corn in diets for growing rabbits.

A total of 70 five-month-old female New Zealand White rabbits were assigned in a completely randomized design, over three reproductive cycles, with two treatments: a reference diet and a half-simplified diet containing 79.83% cassava byproduct. The study evaluated body weight and feed intake of does, feed cost, number and total body weight of kits at kindling and weaning per female during three cycles, number and percentage of mortality/female/cycle, and weight gain of kits from birth to weaning. No interaction was observed between the diets and among the reproductive cycles for any evaluated characteristics. The body weight of does at the moment of weaning was similar in both groups for all three reproductive cycles. However, does fed the half-simplified diet had lower feed intake during the three reproductive cycles and, consequently, more reproductive flaws. The number of kits at weaning, body weight of kits at kindling and weaning, weight gain of kits from birth to weaning, and total body weight of kits at weaning were lower for the group of does fed the half-simplified diet and, consequently, there was a higher number and percentage of dead kits in this group. The total numbers of kits at kindling and weaning and total body weight of kits at birth during all three reproductive cycles were similar between the groups; however, total body weight of weaning rabbits was higher for the animals receiving the reference diet. It is possible to conclude that although the use of the half-simplified diet decreases the reproductive performance of does, it reduces feed cost per kg of body weight by 23.63% compared with the reference diet, proving to be a viable nutritional option for rabbit production.