Relações metionina mais cistina digestível: lisina digestível em dietas suplementadas com ractopamina para suínos em terminação

-Performance and carcass and cut yield of finishing pigs of three sexual categories fed diets with different levels of ractopamine were studied. Forty-eight hybrid animals (initial weight of 92.1±2.4 kg) were distributed in a completely randomised design in 3 × 2 factorial arrangement (three sexual categories: surgically castrated males, two females and immunologically castrated males -with or without 10 ppm of ractopamine), totalling six treatments and eight repetitions with one animal per experimental plot during 28 days. Ractopamine improved weight gain and feed conversion of all sexual categories. The best results were obtained with immunologically castrated males, which, in turn, had lower carcass yield and backfat thickness in the belly. In the absence of ractopamine, depth and loin eye area were higher in females but no differences in these variables were observed between categories when this additive was used. Ractopamine increased the sirloin yield in all sexual categories. There was no difference in bonus index. Ractopamine improves the performance of pigs of 92 to 125 kg.Immunologically castrated males have the best performance responses to ractopamine, but with losses in carcass yield, loin characteristics and backfat thickness of the belly.

“…This result was similar to those found by Pena et al (2008) using ractopamine and Moraes et al (2010) using ractopamine in females and surgically and immunologically castrated males.…”

Section: Resultssupporting

confidence: 90%

Ractopamine in diets for finishing pigs of different sexual categories

Barbosa¹,

Silva²,

Cantarelli³

et al. 2012

“…Além disso, com a deposição de proteína, ocorre maior deposição de água em comparação ao ganho em gordura. Para o ganho de peso, portanto, a deposição de proteína é mais interessante que a de gordura (Pena et al, 2008).…”

Section: Resultsunclassified

Níveis de energia líquida e ractopamina para leitoas em terminação sob conforto térmico

Moura¹,

Kiefer²,

Silva³

et al. 2011

RESUMO -Objetivou-se com este estudo avaliar níveis de energia líquida e ractopamina em dietas para leitoas em terminação sob conforto térmico. Foram utilizadas 40 leitoas com peso inicial de 67,4 ± 3,4 kg, distribuídas em delineamento de blocos ao acaso em esquema fatorial 2 × 4, composto de dois níveis de ractopamina, 0 e 20 ppm, em combinação aos níveis de energia líquida de 2.300; 2.424; 2.548 e 2.668 kcal/kg de ração, com cinco repetições, considerando cada animal uma unidade experimental. O período experimental teve duração de 28 dias. A temperatura do ar, a umidade relativa, a temperatura de globo negro e o índice de temperatura de globo e umidade foram de 21,5 ± 2,8ºC, 91,7 ± 6,8%, 21,7 ± 2,9ºC e 70,1 ± 3,7, respectivamente. Houve interação entre níveis de energia líquida e ractopamina, uma vez que a inclusão de 20 ppm de ractopamina em dietas contendo 2.668 kcal de energia líquida/kg de ração ocasionou redução da espessura de toucinho e aumento da porcentagem de carne magra e do índice de bonificação de carcaças. A inclusão de 20 ppm de ractopamina proporcionou aumento do ganho diário de peso e melhora na conversão alimentar, proporcionando maior peso de carcaça quente e aumentando a quantidade de carne magra nas carcaças. Dietas suplementadas com 20 ppm de ractopamina melhoram o desempenho e aumentam a produção de carne em leitoas em terminação. A ractopamina é ineficiente em reduzir a deposição de gordura e aumentar o percentual de carne magra na carcaça de leitoas alimentadas com dietas contendo baixa concentração de energia. O nível de 2.300 kcal de energia líquida/kg de ração atende à exigência nutricional de leitoas em terminação sob conforto térmico.Palavras-chave: aditivo, ambiente térmico, carcaça, desempenho Net energy and ractopamine levels for finishing gilts under thermal comfortABSTRACT -This research was conducted to evaluate the net energy and ractopamine levels in the diet of finishing gilts kept under thermal comfort conditions. Forty gilts were used, with initial weight of 67.4 ± 3.4 kg, distributed in a randomized blocks design in a 2 × 4 factorial scheme composed of two levels of ractopamine, 0 and 20 ppm, combined with net energy levels of 2,300; 2,424; 2,548 and 2,668 kcal/kg of feed, with five replications, considering each animal per experimental unit.The experimental period lasted 28 days. Air temperature, relative humidity, black globe temperature, and black globe temperature and humidity index were 21.5 ± 2.8ºC, 91.7 ± 6.8%, 21.7 ± 2.9ºC and 70.1 ± 3.7, respectively. There was interaction between net energy levels and ractopamine, once the inclusion of 20 ppm of ractopamine in diets with 2,668 kcal of net energy/kg of feed resulted in a decrease in backfat thickness and consequently an increase in lean meat percentage and in carcass allowance index. The inclusion of 20 ppm of ractopamine caused an increased in daily weight gain, improved feed gain ratio, providing higher hot carcass weight and increasing the lean meat amount in carcasses. Diets supplemented with 20 ppm of rac...

“…The digestible methionine+cystine levels in the diets did not influence (P>0.05) daily feed intake (Table 2). In studies carried out with finishing pigs, Loughmiller et al (1996), Santos et al (2007), and Pena et al (2008) did not observe significant variation in the voluntary feed intake of the animals by increasing the dietary digestible levels of methionine+cystine, neither.…”

Section: Resultsmentioning

confidence: 93%

Levels of digestible methionine+cystine in diets for high genetic potential barrows from 95 to 125 kg

Santos¹,

Donzele²,

Silva³

et al. 2011

Self Cite

This study was carried out to evaluate the effects of increasing levels of digestible methionine+cystine on performance and carcass composition of high genetic potential barrows for lean deposition. Sixty-four barrows with initial weight of 95.46 ± 1.09 kg were allotted to a completely randomized block design, with four levels of digestible methionine+cystine (0.427, 0.466, 0.504, and 0.545%, corresponding to the digestible methionine+cystine:digestible lysine ratios of 57.0, 62.0, 67.0 and 73.0%, respectively), with eight replicates, and two animals per experimental unit. Experimental diets and water were provided ad libitum until the end of the experimental period when pigs reached 125.21 ± 2.49 kg. Levels of digestible methionine+cystine did not affect daily intake, daily weight gain and feed conversion of the animals, but they affected daily intake of digestible methionine+cystine which increased linearly. Levels of digestible methionine+cystine did not affect carcass weight, meat amount, backfat thickness at P2, and daily meat deposition. The digestible methionine+cystine level of 0.427%, corresponding to the digestible methionine+cystine:lysine ratio of 57.0% and to a daily digestible methionine+cystine intake of 14.20 g/d, provides the best performance and carcass traits for high genetic potential barrows in the phase of 95 to 125 kg.