Metabolic and histologic responses of pacu (Piaractus mesopotamicus) fed diets supplemented with increasing concentrations of ractopamine

An experiment was conducted during 60 days with forty pacu males fed diets supplemented with increasing concentrations of ractopamine (0.00, 11.25, 22.50, 33.75, and 45.00 mg kg−1). Eight fish were evaluated for each experimental diet. Performance and survival rate of the fish were measured. At the end of the experiment, blood was collected to determine the levels of cortisol, triacylglycerol, and protein. Moreover, the liver was collected to determine the activities of glucose-6-phosphate dehydrogenase and malic enzymes. The fillets were collected to determine chemical composition, and histologic cuts were analyzed to verify muscle growth and deposition of adipose tissue between muscle fibers. Increasing concentrations of dietary ractopamine did not change feed intake, fillet yield, fillet content of protein and ash, and frequency of relative distribution of muscle fibers. By increasing the dietary ractopamine concentration, the serum cortisol level was elevated. Ractopamine supplementation (45.00 mg kg−1) increased serum levels of triacylglycerol and protein and reduced the activity of hepatic lipogenic enzymes and the survival rate of the fish, probably in response to the high concentration of circulating cortisol. In addition, the higher level of ractopamine supplementation evaluated in this research impaired the weight gain and feed conversion. However, 11.25 mg kg−1 ractopamine reduced the ether extract level determined in the fillet and the fat deposition between muscle fibers, improving the nutritional quality of meat.(AU)

Intoxicação por antibiótico ionóforo em ruminantes alimentados com varredura de fábrica de ração Relato de caso / Ionophore antibiotics poisoning of ruminants after feeding with scraps from a ration factory - case report

Antibióticos ionóforos (AI) são fármacos utilizados em animais, principalmente como coccidiostáticos e promotores de crescimento. Podem causar intoxicação aguda ou crônica, induzindo lesões musculares esqueléticas e/ou cardíacas. São descritos os aspectos epidemiológicos, clínicos e patológicos de um surto de intoxicação por AI em ovinos e bovinos que receberam sobras provenientes de uma fábrica de ração (popularmente conhecidas como varredura). Quatro horas após acesso à ração contaminada alguns ovinos foram encontrados mortos e vários outros estavam doentes. Os bovinos manifestaram sinais um dia após ingestão da ração, com morte após 4 a 20 dias. Estas consistiam em inapetência, fraqueza, relutância em movimentar-se, incoordenação, dispneia, decúbito lateral e morte. Morreram 61 ovinos (42,36% do rebanho) e oito bovinos jovens (24,24% do lote). Duas ovelhas doentes foram encaminhadas ao Setor de Patologia Veterinária da Universidade Federal de Lavras (SPV/DMV/UFLA). Devido à gravidade do quadro clínico foram submetidas a eutanásia. Na necropsia observaram-se áreas pálidas na musculatura, caracterizadas histologicamente por graus variáveis de necrose e regeneração em músculos esqueléticos e cardíaco. A análise cromatográfica (HPLC) de uma amostra da ração utilizada revelou 97,14 mg de monensina/kg de ração. O diagnóstico baseou-se nos achados epidemiológicos, clínicos, lesões macro e microscópicas e na análise toxicológica da ração oferecida aos animais. Embora a utilização de “varredura de fábrica de ração” pareça uma opção economicamente interessante aos produtores ela oferece riscos de intoxicação e/ou morte e não érecomendada.(AU)

Ionophore antibiotics (IA) are drugs used in animals, particularly as coccidiostats and growth promoters. They can cause acute or chronic poisoning, inducing skeletal and / or heart muscle injuries. This paper describes the epidemiological, clinical and pathological aspects of an IA poisoning outbreak in sheep and cattle fed with leftovers from a animal ration factory. Four hours after the access to the contaminated feed, some sheep were found dead and several others were sick. The cattle manifested clinical signs one day after ingestion of the feed, with death 4 to 20 days after clinical onset. The signs consisted of inappetence, weakness, reluctance to move, incoordination, dyspnea, lateral decubitus and death. Of the sheep herd 61 (42.36%), and eight young cattle (24.24% of the lot) died. Two sick sheep were sent to the Veterinary Pathology Sector, Department of Veterinary Medicine of the Federal University of Lavras (SPV/DMV/UFLA). Due to the severity of the clinical condition, both were euthanized. At necropsy were observed pale areas in the muscles, characterized histologically by varying degrees of necrosis and regeneration in skeletal and cardiac muscles. It was performed a chromatographic analysis (HPLC) of a sample of feed, which showed 97.14 mg monensin/kg of feed. The diagnosis was based on epidemiological, clinical, gross and histological findings, and toxicological analysis of the feed used. Although the use of "scan feed mill" seems an economically attractive option for producers it presents risks and is not recommended.(AU)

Intoxicação por antibiótico ionóforo em ruminantes alimentados com varredura de fábrica de ração Relato de caso / Ionophore antibiotics poisoning of ruminants after feeding with scraps from a ration factory - case report

Antibióticos ionóforos (AI) são fármacos utilizados em animais, principalmente como coccidiostáticos e promotores de crescimento. Podem causar intoxicação aguda ou crônica, induzindo lesões musculares esqueléticas e/ou cardíacas. São descritos os aspectos epidemiológicos, clínicos e patológicos de um surto de intoxicação por AI em ovinos e bovinos que receberam sobras provenientes de uma fábrica de ração (popularmente conhecidas como varredura). Quatro horas após acesso à ração contaminada alguns ovinos foram encontrados mortos e vários outros estavam doentes. Os bovinos manifestaram sinais um dia após ingestão da ração, com morte após 4 a 20 dias. Estas consistiam em inapetência, fraqueza, relutância em movimentar-se, incoordenação, dispneia, decúbito lateral e morte. Morreram 61 ovinos (42,36% do rebanho) e oito bovinos jovens (24,24% do lote). Duas ovelhas doentes foram encaminhadas ao Setor de Patologia Veterinária da Universidade Federal de Lavras (SPV/DMV/UFLA). Devido à gravidade do quadro clínico foram submetidas a eutanásia. Na necropsia observaram-se áreas pálidas na musculatura, caracterizadas histologicamente por graus variáveis de necrose e regeneração em músculos esqueléticos e cardíaco. A análise cromatográfica (HPLC) de uma amostra da ração utilizada revelou 97,14 mg de monensina/kg de ração. O diagnóstico baseou-se nos achados epidemiológicos, clínicos, lesões macro e microscópicas e na análise toxicológica da ração oferecida aos animais. Embora a utilização de “varredura de fábrica de ração” pareça uma opção economicamente interessante aos produtores ela oferece riscos de intoxicação e/ou morte e não érecomendada.

Ionophore antibiotics (IA) are drugs used in animals, particularly as coccidiostats and growth promoters. They can cause acute or chronic poisoning, inducing skeletal and / or heart muscle injuries. This paper describes the epidemiological, clinical and pathological aspects of an IA poisoning outbreak in sheep and cattle fed with leftovers from a animal ration factory. Four hours after the access to the contaminated feed, some sheep were found dead and several others were sick. The cattle manifested clinical signs one day after ingestion of the feed, with death 4 to 20 days after clinical onset. The signs consisted of inappetence, weakness, reluctance to move, incoordination, dyspnea, lateral decubitus and death. Of the sheep herd 61 (42.36%), and eight young cattle (24.24% of the lot) died. Two sick sheep were sent to the Veterinary Pathology Sector, Department of Veterinary Medicine of the Federal University of Lavras (SPV/DMV/UFLA). Due to the severity of the clinical condition, both were euthanized. At necropsy were observed pale areas in the muscles, characterized histologically by varying degrees of necrosis and regeneration in skeletal and cardiac muscles. It was performed a chromatographic analysis (HPLC) of a sample of feed, which showed 97.14 mg monensin/kg of feed. The diagnosis was based on epidemiological, clinical, gross and histological findings, and toxicological analysis of the feed used. Although the use of "scan feed mill" seems an economically attractive option for producers it presents risks and is not recommended.