Inclusão da ractopamina na nutrição de peixes: revisão de literatura / Inclusion of ractopamine in fish nutrition: literature review / Inclusión de ractopamina en nutrición de peces: revisión de literatura

A demanda da população mundial por produtos aquáticos esta se incrementando, enquanto que a produção da pesca extrativa reduzindo, alcançando em muitos casos, seu máximo potencial produtivo. Como consequência, não será possível em curto prazo, sustentar o fornecimento de produtos aquáticos, direcionado a uma população que constantemente cresce e demanda pescados. O setor produtivo segue a tendência atual de outros sistemas de produção animal, os quais vêm buscando o aumento da produtividade, de maneira sustentável, do ponto de vista econômico e ambiental, requerendo, principalmente, o aporte da nutrição para contribuir com essa tendência. Os estudos com os aditivos adicionados a dieta dos animais de cativeiro é uma estratégia que tem demonstrado alto potencial para sua inclusão na aquicultura, havendo a possibilidade de um aumento nos índices produtivos e/ou melhora na qualidade do produto para o consumidor. A ractopamina é um aditivo classificado como um agonista beta-adrenérgico e seu mecanismo de ação esta associado com efeitos sobre o metabolismo dos peixes que diminuem o acúmulo de gorduras, por meio da inibição da lipogêneses e estimulo da lipólise, e por mecanismos que favorecem a síntese de proteínas muscular. Os estudos realizados até o momento comprovam que existem alterações metabólicas nos peixes, embora, não se tem encontrado, em todos os estudos, diferenças significativas nos índices zootécnicos, para assim, estabelecer seu uso na indústria. A realização de mais pesquisas é necessária para o melhor entendimento da ractopamina na alimentação dos peixes, sobretudo, no entendimento dos receptores e mecanismos de ação dos peixes.(AU)

The demand of the global population for aquatic products is increasing while the production of extractive fisheries is reducing, and, in many cases, even reaching its maximum productive potential. As a consequence, it will not be possible in the short term to sustain the supply of aquatic products aimed at a population in constant growth and in demand for fish. The productive sector follows the current trend of other animal production systems, which have been seeking to sustainably increase productivity from an economic and environmental point of view, mainly requiring the contribution of nutrition to this trend. Studies with additives to the diet of captive animals is a strategy that has shown high potential for inclusion in aquaculture, with the possibility of an increase in production rates and/or improvement in the quality of the product for the consumer. Ractopamine is an additive classified as a beta-adrenergic agonist and its mechanism of action is associated with effects on fish metabolism that reduce the accumulation of fats through the inhibition of lipogenesis and stimulation of lipolysis, and by mechanisms that favor the synthesis of muscle protein. The studies carried out so far prove that there are metabolic changes in fish, although no significant differences have been found in zootechnical indexes in order to establish its use in the industry. Further research is required for a better understanding of ractopamine in fish nutrition, especially in understanding the receptors and mechanisms of action in fish.(AU)

La demanda de la población mundial por productos acuáticos va en aumento, mientras que la producción de la pesca extractiva se reduce, alcanzando, en muchos casos, su máximo potencial productivo. Como consecuencia, no será posible en corto plazo sostener el suministro de productos acuáticos, dirigidos a una población que crece constantemente y demanda pescado. El sector productivo sigue la tendencia actual de otros sistemas de producción animal, que han venido buscando incrementar la productividad, de manera sostenible, desde el punto de vista económico y ambiental, requiriendo, principalmente, del aporte de la nutrición para contribuir a esa tendencia. Los estudios con aditivos agregados a la dieta de animales en cautiverio es una estrategia que ha mostrado un alto potencial para su inclusión en la acuicultura, con posibilidad de incremento en los índices de producción y/o mejora en la calidad del producto para el consumidor. La ractopamina es un aditivo clasificado como agonista beta-adrenérgico y su mecanismo de acción está asociado con efectos sobre el metabolismo de los peces que reducen la acumulación de grasas, a través de la inhibición de la lipogénesis y estimulación del lipólisis, y por mecanismos que favorecen la síntesis de proteínas musculares. Los estudios realizados hasta el momento prueban que existen cambios metabólicos en los peces, aunque en todos los estudios no se han encontrado diferencias significativas en los índices zootécnicos, con el fin de establecer su uso en la industria. Se necesita más investigación para comprender mejor la ractopamina en la nutrición de los peces, especialmente para comprender los receptores y los mecanismos de acción en los peces.(AU)

Monogenoidea parasites of Oreochromis niloticus submitted to ractopamine supplemented diet from cultivated system / [Monogenoidea parasitos de Oreochromis niloticus provenientes de sistema de cultivo submetidos a uma dieta suplementada com ractopamina]

Oreochromis niloticus (Linnaeus) (Perciformes: Cichlidae), commonly named "tilapia", is the second most cultivated species in the world. Among the diseases that affect tilapia are parasitic diseases caused by parasites of the class Monogenoidea. The aim of the present study was to analyze parasitism rates among specimens of O. niloticus in farming systems, after dietary supplementation with ractopamine, a growth promoter that is used for fattening fish. The action of this substance on the quantitative parameters of infestation by Monogenoidea was evaluated. Samples of O. niloticus were obtained from a fish farm in Brasília, Federal District, Brazil. Their gills were removed and fixed. Four species of monogenoideans were collected: Cichlidogyrus halli, C. sclerosus, C. thurstonae and Scutogyrus longicornis. The results from this study indicate that the monogenoidean parasites of tilapias examined here presented different behaviors in relation to the ractopamine concentrations that were added to the food. The parasitological indexes did not present significant reductions through using ractopamine, thus leading to the conclusion that administration of ractopamine is not efficient as a method for controlling infestations of monogenoidean parasites.(AU)

Oreochromis niloticus (Linnaeus) (Perciformes: Cichlidae), tilápia, é a segunda espécie mais cultivada no mundo. Entre outras doenças que afetam a tilápia, estão as doenças provocadas por parasitos da classe Monogenoidea. O presente estudo teve como objetivo analisar os índices de parasitismo em espécies de O. niloticus provenientes de sistemas de cultivo, submetidos a uma dieta com suplementação de ractopamina, usada como promotor de crescimento no estágio de engorda dos peixes, para avaliar as ações dessa substância nos parâmetros quantitativos da infestação por Monogenoidea. Exemplares de O. niloticus obtidos na piscicultura "Agropecuária do Buriti Perdido", em Brasília, Distrito Federal, Brasil, foram examinados; as brânquias foram removidas e fixadas. Quatro espécies foram coletadas: Cichlidogyrus halli, C. sclerosus, C. thurstonae e Scutogyrus longicornis. Os resultados obtidos no presente estudo indicaram que as espécies de Monogenoidea parasitos de tilápia examinadas apresentam diferentes comportamentos relacionados à concentração de ractopamina adicionada ao alimento. Os índices parasitológicos não apresentaram redução significativa pelo uso da ractopamina, levando à conclusão de que a ractopamina não é eficiente como método de controle parasitário em infestações por Monogenoidea.(AU)

Novel ractopamine-protein carrier conjugation and its application to the lateral flow strip test for ractopamine detection in animal feed / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

In this work, a novel conjugate of ractopamine and bovine serum albumin (RAC-BSA) has been developed via the Mannich reaction, with a mole coupling ratio for RAC-BSA of 9:1. The proposed conjugation method provides a simple and one-step method with the use of fewer reagents compared with other conjugation methods for competitive immunoassays. RAC-BSA conjugation was used to fabricate a competitive lateral flow strip test for RAC detection in animal feed. For sample preparation, RAC was spiked in swine feed purchased from the local markets in Thailand, and methanol and running buffer at a volume ratio of 10:90 was used as extraction buffer. The procedures for sample preparation were completed within 25 min. Under optimal conditions, the limit of detection (LOD), assessed by the naked eye within 5 min, was found to be 1 ng/g. A semi-quantitative analysis was also conducted using a smart phone and computer software, with a linearity of 0.075-0.750 ng/g, calculated LOD of 0.10 ng/g, calculated limit of quantitation of 0.33 ng/g, and good correlation of 0.992. The recoveries were found in the range of 96.4%-103.7% with a relative standard deviation of 2.5%-3.6% for intra- and inter-assays. Comparison of the results obtained by the strip test with those obtained by enzyme-linked immunosorbent assay had a good agreement in terms of accuracy. Furthermore, this strip test exhibited highly specific RAC detection without cross reactivity with related compounds. Therefore, the RAC-BSA conjugation via the Mannich reaction can be accepted as a one-step and easy conjugation method and applied to the competitive lateral flow strip test.

Novel ractopamine–protein carrier conjugation and its application to the lateral flow strip test for ractopamine detection in animal feed / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

In this work, a novel conjugate of ractopamine and bovine serum albumin (RAC–BSA) has been developed via the Mannich reaction, with a mole coupling ratio for RAC–BSA of 9:1. The proposed conjugation method provides a simple and one-step method with the use of fewer reagents compared with other conjugation methods for competitive immunoassays. RAC–BSA conjugation was used to fabricate a competitive lateral flow strip test for RAC detection in animal feed. For sample preparation, RAC was spiked in swine feed purchased from the local markets in Thailand, and methanol and running buffer at a volume ratio of 10:90 was used as extraction buffer. The procedures for sample preparation were completed within 25 min. Under optimal conditions, the limit of detection (LOD), assessed by the naked eye within 5 min, was found to be 1 ng/g. A semi-quantitative analysis was also conducted using a smart phone and computer software, with a linearity of 0.075–0.750 ng/g, calculated LOD of 0.10 ng/g, calculated limit of quantitation of 0.33 ng/g, and good correlation of 0.992. The recoveries were found in the range of 96.4%–103.7% with a relative standard deviation of 2.5%–3.6% for intra- and inter-assays. Comparison of the results obtained by the strip test with those obtained by enzyme-linked immunosorbent assay had a good agreement in terms of accuracy. Furthermore, this strip test exhibited highly specific RAC detection without cross reactivity with related compounds. Therefore, the RAC–BSA conjugation via the Mannich reaction can be accepted as a one-step and easy conjugation method and applied to the competitive lateral flow strip test.

Metabolic and behavioral effects of ractopamine at continuous low levels in rats under stress

This study aimed at evaluating the effect of ractopamine (RAC) on metabolism, zootechnical performance, body composition, and behavior in Wistar rats submitted to acute and chronic restrain stress. The oral dose of 5 mg/kg of RAC was administered in periods of 0, 7, 14, 21, and 28 days. The elevated plus-maze test (EPMT) was used for behavioral assessment. Blood, carcass and viscera characteristics were evaluated. Insulin-dependent glucose transporters (GLUT-4) were semi-quantified by Western Blot in epididymal adipocytes. RAC periods associated with chronic stress increased the GLUT-4 protein expression in adipose tissue in a time-dependent manner (P=0.01), i.e., the longer the RAC addition period, the higher the GLUT-4 concentration in chronically stressed animals (0=1.42; 7=1.19; 14=2.03; 21=1.59; 28=2.35). The stress periods combined with RAC increased the time spent in the opened arms of the maze (Chronic stress: 0=10.6; 7=8.7; 14=5.9; 21=12.3; 28=4.0; Acute stress 0=3.1; 7= 4.7; 14=7.5; 21=0.0; 28=2.8) (P=0.04). Chronic (entries on the closed arms [ECA]=3.60) and acute (ECA=3.80) stress reduced locomotive activity in the maze (P=0.03). The results suggested that stress could negatively affect the possible benefits offered by the RAC, mainly impairing the adipose tissue metabolism and behavior in the animals.

Características de carcaça e da carne de suínos machos castrados e imunocastrados alimentados com diferentes níveis nutricionais / Carcass characteristics and meat of surgically castrated and immunocastrated pigs fed different nutritional levels

O trabalho foi realizado para avaliar as características de carcaça e carne de suínos machos castrados e imunocastrados alimentados com dietas contendo diferentes níveis nutricionais. O delineamento experimental foi inteiramente casualizado com quatro tratamentos principais (T1-suínos machos castrados alimentados com dieta basal; T2-machos imunocastrados alimentados com dieta basal; T3-machos imunocastrados alimentados com dieta basal+3% aminoácidos e energia; T4-machos imunocastrados alimentados com dieta basal+5% aminoácidos e energia) e dois tratamentos secundários com ou sem ractopamina dentro de cada tratamento principal. Os suínos machos castrados apresentaram peso de abate 3,3% inferior (P<0,05), peso de carcaça fria 1,4% superior (P<0,05) e peso de carré 13% superior (P<0,05) em relação aos machos imunocastrados. Suínos machos imunocastrados suplementados com 5% a mais de aminoácidos e energia apresentaram costela 19% mais (P<0,05) pesada e valores superiores (P<0,05) na coloração b* (amarelo-azul) na carne aos 45min e às 24h pós-abate em relação aos machos castrados alimentados com a dieta basal. A suplementação com 5% de aminoácidos e energia aumenta o peso e rendimento de costela e altera o valor da coloração b* (amarelo-azul) na carne aos 45min e às 24h pós-abate de suínos machos imunocastrados.

The study was carried out to evaluate the carcass characteristics and meat of surgically castrated and immunocastrated pigs fed with different nutritional levels. The animals were distribuited in a completely randomized experimental design with four main treatments (T1-surgically castrated pigs fed with basal diet; T2-immunocastrated pigs fed with basal diet; T3-immunocastrated pigs fed with basal diet+3% amino acids and energy; T4-immunocastrated pigs fed with basal diet+5% amino acids and energy) and two secondary treatments with or without ractopamine within each main treatment. The surgically castrated pigs had slaughter weight 3.3% lower (P<0.05), cold carcass weight 1.4% higher (P<0.05) and loin chop weight 13% higher (P<0.05) compared to immunocastred pigs. The immunocastrated pigs supplemented with 5% more amino acids and energy had rib 19% more heavier (P<0.05) and higher values (P<0.05) in the color b* (yellow-blue) in the meat to 45min and 24h post-slaughter compared with surgically castrated pigs fed with basal diet. Supplementation with 5% amino acids and energy increases weight and yield of rib and changes the value of color b* (yellow-blue) in the meat to 45min and 24h post-slaughter male pigs immunocastrated.

Efeito da ractopamina e de métodos de formulação de ração sobre o desempenho e as características de carcaça de leitoas em terminação / Effect of ractopamine and methods of diet formulation on performance and carcass characteristics of finishing gilts

Avaliou-se o efeito da ractopamina e de diferentes métodos de formulação de dietas sobre o desempenho e as características de carcaça de leitoas em terminação. Foram utilizadas 60 leitoas, híbridas comerciais, distribuídas em delineamento experimental de blocos ao acaso, em esquema fatorial 2x3, sendo dois níveis de ractopamina e três métodos de formulação de dietas. Houve interação de métodos de formulação versus ractopamina para ganho de peso diário, peso corporal, conversão alimentar e taxa de deposição de carne magra (TDCM) na avaliação de carcaça in vivo por ultrassom. A dieta formulada com alta proteína bruta proporcionou maior consumo de dieta (CRD), de lisina (CLD), ganho de peso diário (GPD) e peso corporal final. A suplementação de ractopamina não influenciou o CRD e o CLD, entretanto aumentou o GPD. O método de formulação da dieta não influenciou as características de carcaça aos 28 dias, enquanto a suplementação de ractopamina reduziu a espessura de toucinho, aumentou a profundidade de lombo e o rendimento de carne magra. A dieta formulada com alta proteína bruta proporcionou melhores resultados de desempenho e taxa de deposição de carne magra na carcaça de leitoas em terminação, suplementadas com ractopamina.

The effect of ractopamine supplementation and feed formulation methods was evaluated on performance and carcass characteristics of finishing gilts. Sixty animals were allotted in a completely randomized block experimental design, in a 2x3 factorial scheme - ractopamine (0 and 5ppm) X three feed formulation methods. Interactions between feed formulation method and ractopamine for daily weight gain (DWG), body weight, feed:gain (DFG), and lean carcass meat deposition (LCMD) were by in vivo carcass evaluation using ultrasound observed. Daily feed intake (DFI), lysine intake (DLI), DWG, and final body weight were higher for diets with high protein level. Ractopamine supplementation did not affect feed intake, and lysine intake, but increased daily weight gain. Feed formulation method affected carcass characteristics recorded at 28 days, while ractopamine supplementation reduced backfat thickness, increased muscle depth, and lean carcass proportion of the gilts. Ractopamine improved performance and carcass characteristics of finishing gilts and feed formulation methods affected performance and carcass characteristics. Better performance and higher lean carcass deposition were observed for finishing gilts fed high protein level diets supplemented with ractopamine.

Continuous Detection Method for Ractopamine with Surface Plasmon Resonance Biosensor / 分析化学

The interaction between the anti-Ractopamine (Rac) monoclonal antibody and the Rac derivation immobilized on the sensor chip surface was studied with surface plasmon resonance (SPR) biosensor. A continuous detection method based on the linear response during the association phase was developed. The sensor chip surface was regenerated after several tests performed continuously, thus the detection step was simplified and the life span of the chip was prospected to be prolonged. The detection was performed as an inhibitive immunoassay. The mixture of anti-Rac monoclonal antibody and the sample flowed over the surface with Rac derivation was immobilized. The relative response was in inversely proportion to the concentration of Rac. The detection limit was less than 4 μg/L with a detection time of 15 min.

Efecto del nivel de clorhidrato de ractopamina y proteína en la dieta sobre el desempeño productivo y rendimiento en canal de pavos comerciales / Effect of ractopamine hydrochloride and protein level in the diet on the performance and carcass yield of growing turkeys

The effect of ractopamine hydrochloride (0, 5 or 10 ppm) and protein (22% and 24%) in the diet on the productive performance and carcass yield of growing turkeys was evaluated. Seventy two male turkeys from the Nicholas-700 line of 14 weeks old were used. The turkeys were fed ad libitum with the experimental diets during 28 days. The turkeys assigned to the treatments with ractopamine (RAC) had higher daily gains of weight (0.139, 0.154 and 0.156 kg/day for 0, 5 and 10 ppm, respectively) and were 400 and 500 g heavier at the end of the experiment (12.9 and 13.0 kg for 5 and 10 ppm respectively) than the turkeys of treatment 0 ppm of RAC (12.5 kg). RAC increased significantly (P < 0.05) the weight of the thigh (0.748, 0.793 and 0.809 kg for 0, 5 and 10 ppm) and wing (P < 0.06; 0.593, 0.589 y 0.626 for 0, 5 and 10 ppm). There was no effect of protein treatment and RAC on breast yield (P > 0.05). The results obtained in this work indicated that the RAC increased the daily weight gain and the yield of the thigh and wing from a concentration of 5 ppm in the diet.

Se evaluó el efecto del nivel de clorhidrato de ractopamina (0, 5 o 10 ppm) y proteína (22% y 24%) en la dieta sobre el desempeño productivo y rendimiento en canal de pavos comerciales. Se utilizaron 72 pavos machos de la línea Nicholas-700 de 14 semanas de edad. Los pavos se alimentaron ad libitum con dietas experimentales durante 28 días. Se encontró que los pavos asignados a los tratamientos con clorhidrato de ractopamina (CLRP) tuvieron mayores ganancias diarias de peso (0.139, 0.154 y 0.156 kg/ día, para 0, 5 y 10 ppm, respectivamente) y ganaron entre 400 y 500 g más peso al final del experimento (12.9 y 13.0, para 5 y 10 ppm respectivamente) que los pavos del tratamiento 0 ppm de CLRP (12.5 kg). Se encontró que el CLRP incrementó significativamente, (P < 0.05) el peso del muslo (0.748, 0.793 y 0.809 para 0, 5 y 10 ppm) y del ala (P < 0.06; 0.593, 0.589 y 0.626 para 0, 5 y 10 ppm). No se observó ningún efecto del nivel de proteína y de CLRP sobre el rendimiento de pechuga (P > 0.05). Los resultados obtenidos en este trabajo indican que el CLRP puede incrementar la ganancia diaria de peso y el rendimiento del muslo y el ala, desde 5 ppm.

Efeitos da ractopamina e de dois níveis de lisina digestível na dieta sobre o desempenho e características de carcaça de leitoas em terminação / Effects of ractopamine and two lysine levels on performance and carcass traits of gilts in the finishing phase

Avaliaram-se os efeitos da ractopamina e de dois níveis de lisina digestível na dieta sobre o desempenho e características de carcaça de leitoas com peso corporal a partir de 85kg, durante 21 e 28 dias antes do abate, os quais foram distribuídos em delineamento experimental de blocos ao acaso com cinco repetições de dois animais por unidade experimental. Os tratamentos consistiram de arranjo fatorial 2x2, com dois níveis de lisina digestível (LD), 0,67 e 0,87 por cento, e dois níveis de ractopamina (0 e 5ppm). Observou-se efeito significativo do nível de LD sobre o ganho de peso e peso corporal e interação significativa (P<0,05) entre o nível de LD e a ractopamina sobre a conversão alimentar e sobre a taxa de deposição de carne magra corporal. Não houve efeito significativo (P>0,05) do nível de LD sobre a espessura de toucinho, profundidade de lombo e rendimento em carne magra da carcaça de acordo com avaliação da carcaça, feita in vivo. Não houve efeito (P>0,05) da ractopamina sobre o consumo de ração, o ganho de peso diário e o peso corporal aos 21 e 28 dias de experimento. A ractopamina reduziu a espessura de toucinho no ponto P2 aos 21 dias e aumentou o rendimento de carne magra e a profundidade de lombo na avaliação da carcaça no frigorífico.

The effects of ractopamine and digestible lysine levels on performance and carcass traits of gilts with initial body weight average of 85kg, recorded during 21 and 28 day before slaughtering time were evaluated in a completely randomized block design with five replicates of two animals per experiment unit. The treatments consisted in a 2 x 2 factorial scheme, two levels of digestible lysine (DL) (0.67 and 0.87 percent) and two ractopamine levels (0 and 5ppm). Significant effects of DL on daily weight gain and body weight and significant effects of DL and ractopamine level were observed for feed:weight gain ratio and lean meat carcass deposition. No significant effects (P>0.05) of DL on fat thickness, muscle depth and lean meat yield according to the in vivo carcass evaluation were observed. No significant effect of ractopamine (P>0.05) on feed intake, daily weight gain and body weight (21 and 28 days) were observed. Ractopamine reduced back fat thickness at P2 point (21days) and increased lean meat yield and muscle depth in frigorific carcass evaluation.