Ractopamine as a metabolic modifier feed additive for finishing pigs: a review

The β-adrenergic agonist ractopamine is increasingly used in the swine industry due to higher consumer demand for leaner pork products. Redirecting nutrients to favor leanness rather than fat deposition, ractopamine improves growth and carcass traits of finishing pigs. However, the impact of this agonist on pork quality is not clearly defined. Understanding the biological effects of dietary ractopamine dose, treatment period, lysine levels, and the lysine to metabolizable energy ratio will help pork producers achieve improvements in animal performance, carcass leanness, and economic efficiency in swine production systems

Weaned piglets fed diets with milk protein and supplemental zinc

Avaliaram-se os efeitos da utilização de proteína láctea ou zinco suplementar na dieta sobre o desempenho, os pesos relativos do intestino delgado e fígado, a morfologia intestinal e as concentrações séricas de IGF-I (fator de crescimento semelhante à insulina), hormônio do crescimento e zinco em leitões. O experimento teve duração de 14 dias e foi realizado com 60 leitões desmamados aos 21 dias de idade (5,43 ± 0,46 kg), em delineamento de blocos casualizados, em fatorial 2 x 2, composto de dois níveis de proteína láctea (com e sem, 4%) e dois de zinco (com e sem, 2.250 ppm) na dieta. No período de 1 a 7 dias de experimento, o zinco proporcionou melhor conversão alimentar e, no período de 1 a 14 dias, promoveu maior pesos aos 14 dias e maior ganho de peso. O fornecimento de proteína láctea na dieta piorou a conversão alimentar nas duas fases (de 1 a 7 dias e de 1 a 14 dias de experimento) e resultou em menor profundidade de cripta no jejuno aos 7 dias e maior altura de vilosidade aos 14 dias de experimento. Aos 7 dias de experimento, Houve interação proteína láctea e zinco para a relação altura de vilosidades:profundidade de criptas do jejuno, a qual foi também maior nos animais recebendo proteína láctea. A adição de zinco na dieta reduziu a concentração de IGF-I e o peso relativo do fígado aos 14 dias de experimento, enquanto o uso de proteína láctea aumentou a concentração de IGF-I. A inclusão de proteína láctea melhorou a conversão alimentar, influenciou a morfologia intestinal e aumentou a concentração de IGF-I, mas a suplementação de zinco não foi eficiente para alterar os níveis de hormônio do crescimento no organismo.It was evaluated the effects of using milk protein or supplemental zinc in the diet on performance, relative weights of small intestine and liver, intestine morphology and IGF-I (insulin-like growth factor) serum concentrations, growth hormone and zinc in piglets. The experiment lasted 14 days and it was carried out using 60 piglets weaned at 21 days of age (5.43 ± 0.46 kg) in a complete random design, in a 2 x 2 factorial composed of two levels of milk protein (with and without, 4%) and two levels of zinc (with or without, 2,250 ppm) in the diet. In the 1-7 day experiment period, zinc provided better feed conversion and the in the 1-14 day experiment period, it promoted higher body weight at 14 days and higher weight gain. Supply of milk protein in the diet worsened feed conversion in the two phases (from 1 to 7 days and from 1 to 14 days of the experiment) and it resulted in a lower crypts depth in the jejunum and a higher villous height on day 14 of the experiment. On the 7th day of the experiment, there was an interaction among milk protein and supplemental zinc for villous height:crypts depth relationship, which was also higher for animals fed milk protein. The addition of zinc in the diet reduced insuline-like growth factor concentration and the average weight of the liver on day 14 of the experiment while the use of milk protein increased IGF-I concentrations. The inclusion of milk protein improves feed conversion, affects intestine morphology and increases IGF-I concentration, but supplementation of zinc is not efficient to affect levels of growth hormone in the organism.Zinpro Performance Mineral

Ractopamine, chromium-methionine and their combinations as metabolism modifier feed additives of growing and finishing pigs

Objetivou-se neste estudo avaliar o efeito da adição de ractopamina, cromo-metionina e suas combinações em dietas para suínos em crescimento e terminação sobre o desempenho, as características de carcaça e a qualidade da carne. Sessenta e quatro suínos da linhagem Topigs, com peso inicial de 26,56 ± 3,11 kg, foram distribuídos em delineamento experimental de blocos casualizados em esquema fatorial 2 x 2, com dois níveis de ractopamina (0 e 5 ppm) e dois níveis de cromo-metionina (0 e 400 ppb), totalizando quatro dietas com oito repetições (blocos) por dieta. Em cada uma das três fases, crescimento 1 (de 26,56 kg aos 50,51 kg), crescimento 2 (de 50,51 kg aos 70,32 kg) e terminação (de 70,32 kg aos 114,80 kg), os animais receberam rações fareladas e água à vontade. Ao atingirem o peso vivo de 114,80 ± 4,98 kg, os animais foram abatidos e as carcaças avaliadas quanto ao rendimento de carcaça fria, ao comprimento de carcaça, à espessura de toucinho, à área de olho-de-lombo e à relação gordura:carne. Amostras do músculo longissimus dorsi foram retiradas para mensurações de cor, pH final e perda de peso por gotejamento. A suplementação de ractopamina melhorou a conversão alimentar, o rendimento de carcaça fria, a área de olho-de-lombo, a relação gordura:carne e a perda de peso por gotejamento e reduziu os teores de vermelho e amarelo da carne. O cromo-metionina, embora tenha ocasionado redução no consumo diário de ração, não altera as características de desempenho e de carcaça nem a qualidade da carne dos suínos. A suplementação de ractopamina associada a cromo-metionina não afeta o desempenho nem as características de carcaça e qualidade da carne dos animais.The purpose of this study was to evaluate the effect of ractopamine and chromium-methionine additions and their combinations in diets for growing and finishing swines on performance, carcass traits and meat quality. Sixty-four Topigs line swines at 26.56 ± 3.11 kg initial body weight were distributed in a randomized block experimental design in a 2 x 2 factorial scheme with two levels of ractopamine (0 and 5 ppm) and two levels of chromium-methionine (0 and 400 ppb), totaling four diets with eight replications (blocks) per diet. In each one of the three following phases, growing 1 (from 26.56 kg to 50.51 kg), growing 2 (from 50.51 kg to 70.32 kg) and finishing (from 70.32 kg to 114.80 kg), meal rations and water were given ad libitum to animals.When pigs reached 114.80 ± 4.98 kg body weight, they were slaughtered and carcasses were evaluated regarded to cold carcass yield, carcass length, backfat thickness, loin eye area and fat:meat ratio. Samples of longissimus dorsi muscle were taken to measure colour, final pH and drip loss. Supplementation of ractopamine improved feed conversion, cold carcass yield, loin eye area, fat:meat ratio and drip loss, and it reduced redness and yellowness components of meat. Although chromium-methionine decreased daily feed intake, it does not affect the performance and carcass traits neither meat quality of swines. Supplementation of ractopamine combined to chromium-methionine do not affect carcass traits and meat quality of animals

NUTRITIONAL RELATIONSHIP OF LYSINE AND MONOVALENT CATIONS IN RATS AND SWINE

Four experiments were conducted with rats fed corn-soybean meal diets to test dietary lysine (lys) levels from 0.36 to 1.00% in combination with K levels from 0.36 to 1.00% or Na levels from 0.13 to 1.00%. In another trial, five K sources were tested in combination with two dietary levels of lys (0.36 and 0.68%); two control diets, without supplemental K, were included. Based on performance, the estimated lys requirement was 0.79 to 0.89%. The lys requirement was increased at the higher Na levels. Na showed a detrimental effect on performance, which was accentuated in rats fed low lys diets. Supplemental K tended to depress the performance of rats. In terms of weight gain, potassium carbonate and citrate were less detrimental than K phosphate, but all other K sources were statistically equivalent. The increase in liver weight in lys supplemented rats may be due to an increase in protein synthesis. The increase in kidney weight, by adding lys to the diet, may be due to a reduction in urea excretion. In two trials with swine, supplementation of a corn-soybean meal diet (0.75% lys) with lys up to 0.95% improved performance of 4-week-old weaned pigs. It appears that the lys requirement of baby pigs is 0.95% of the diet or higher. Results obtained with supplemental K up to 1.00% were variable. In one trial, supplemental K improved and in another, it depressed performance of pigs. K level of the basal diet (0.58%) appeared to be adequate. Serum or plasma lys increased in both species by adding lys to the diet. Supplemental lys increased hematocrit and decreased lys in red blood cells of swine. In rats, serum lys, arginine, K and Na were not affected by K sources, and in pigs, they were not affected by supplemental K. In some cases, these parameters had variable responses to the addition of one nutrient at different levels of the other nutrients in the diet, suggesting some interrelationship. In general, for both species, K and/or Na did not alleviate a lys deficiency in corn-soybean meal diets and, in most cases, supplementation of either appeared depressive

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O objetivo do presente trabalho foi estudar a influência da adição de vários níveis de levedura seca (LS) de destilarias de álcool de cana de açúcar em rações de suínos em crescimento e acabamento, sobre a performance e qualidade de carcaça dos animais. Foram utilizadas 36 marrãs, mestiças das raças Large White X Landrace X Wessex, distribuídas de acordo com o peso em doze lotes, os quais foram submetidos a quatro tratamentos: T1 - 0% LS; T2 - 7% LS; T3 - 14% LS; e T4 - 21% LS. A LS substituiu parte do milho e farelo de soja, mantendo os níveis de 16 e 14% de proteína bruta nas rações de crescimento (21,17 a 59,78 kg de peso vivo) e acabamento (59,78 a 97,41 kg de peso vivo), respectivamente. As rações experimentais foram suplementadas com vitaminas, minerais, antibiótico e antioxidante. Os ganhos diários de peso (kg), consumos diários de ração (kg) e conversões alimentares, observados nos tratamentos T1, T2, T3 e T4, foram, respectivamente, 0,673, 1,83 e 2,71; 0,710, 1,99 e 2,80; 0,696, 2,00 e 2,88; e 0,679, 2,01 e 2,96 na fase de crescimento; 0,686, 2,50 e 3,65; 0,662, 2,45 e 3,70; 0,679, 2,60 e 3,84; e 0,710, 2,83 e 3,98 na fase de acabamento; 0,680, 2,16 e 3,18; 0,686, 2,22 e 3,23; 0,688, 2,30 e 3,34; e 0,694, 2,41 e 3,48 no período total. Foi observada uma tendência em aumentar o consumo de ração na fase de crescimento e aumentos lineares da ordem de 0,0160 e 0,0119 kg/dia para cada 1% de LS nas fases de acabamento e crescimento-acabamento, respectivamente. No estudo dos dados referentes à conversão alimentar, foram constatados aumentos nos seus valores numéricos de 0,0122, 0,0161 e 0,0145 para cada 1% de LS na ração, nas respectivas fases de crescimento, acabamento e crescimento-acabamento. O aumento do consumo diário e a pior conversão alimentar foram atribuídos à redução do nível energético das rações, ocasionada pelos níveis crescentes de LS nas mesmas. Com relação à qualidade de carcaça, as médias dos tratamentos T1, T2, T3 e T4 foram, respectivamente, 3,38, 3,23, 3,14 e 3,14 cm para espessura de toicinho; 0,77, 0,73, 0,66 e 0,66 para relação gordura-carne; 30,12, 30,84, 30,84 e 31,39% para percentagem de pernil; 31,2, 33,9, 32,4 e 32,6 cm2 para área de olho de lombo; 79,61, 79,76, 79,09 e 78,83% para rendimento de carcaça; e 95,6, 94,8, 95,6 e 97,4 cm para comprimento de carcaça. Para cada 1% de aumento de LS na ração, foram observadas variações de -0,0057 na relação gordura-carne e 0,0556 na percentagem de pernil. Houve uma tendência em reduzir a espessura de toicinho e o rendimento de carcaça, enquanto que o comprimento de carcaça e a área de olho de lombo não foram afetados. A melhoria da qualidade de carcaça foi atribuída ao aumento do consumo diário de proteína e lisina. Os resultados indicaram a possibilidade do uso da LS como fonte de proteína para suínos em crescimento e acabamento, pelo menos até 21% da ração.Thirty six Large White X Landrace X Wessex crossbred gilts were used to study the influence of three levels of sugar-cane alcohol distillers' dried yeast (DY) in growing and finishing swine rations on performance and carcass quality. The animals were allotted on the basis of body weight in twelve lots of three animals each. The lots were randomly assigned to one of the four following treatments: T1 - 0% DY; T2 - 7% DY; T3 - 14% DY; and T4 - 21% DY. The DY replaced part of the corn and soybean meal, maintaining the 16 and 14% crude protein levels in growing (21,17 to 59,78 kg live weight) and finishing (59,78 to 97,41 kg live weight) diets, respectively. The experimental rations were supplemented with vitamins, minerals, antibiotic and antioxidant. Although the DY levels in the ration did not influence (P < 0,05) the daily gain, there was a tendency to increase the daily ration intake in the growing phase. A linear increase (P < 0,01) of daily ration intake was observed in the finishing (Y&#770; = 2,4270 + 0,0160X) and growing-finishing (Y&#770; = 2,1480 + 0,0119X) phases. The feed/gain ratio increased linearly with the increased levels of DY in the diet, in the growing (Y&#770; = 2,7087 + 0,0122x), in the finishing (Y&#770; = 3,6260 + 0,0161X) and in the growing-finishing (Y&#770; = 3,1563 + 0,0145X) phases. The increased daily ration intake gain and feed/gain ratio were attributed to the reduction of the ration energy levels due to DY addition. Increasing the DY levels in the diet, showed an improvement of carcass quality, since there was a tendency of reduction in the backfat thickness, a linear reduction (P < 0,05) in the fat-lean ratio (Y&#770; = 0,7700 - 0,0057X) and a linear increase (P < 0,05) in the ham percentage (Y&#770; = 30,2443 + 0,0556X). There was also a tendency to reduce the dressing percentage, while the carcass lenght and the loin-eye area were not affected by DY addition. The improved carcass quality of swine fed rations containing high DY levels was attributed to the increased daily intake of protein and lisine. This experiment showed that the DY may be used as a protein source for growing and finishing swine up to 21% of the ration