Carcass yield and proximate composition of bullfrog (Lithobates catesbeianus)

This work evaluated five classes of weight of bullfrog (Lithobates catesbeianus) seeking to define the ideal slaughter weight for the species. We used 79 bullfrogs, distributed in a completely randomized design (class 1 < 100 g (n = 10); class 2 from 101 to 150 g (n = 17); class 3 from 151 to 200 g (n = 24); class 4 from 201 to 250 g (n = 14); and class 5 >251 g (n = 14)), which were euthanized, weighted and gutted. For the carcass yield, we weighed the clean torso, thighs, liver, skin and head. The clean torso was subjected to chemical composition analysis. The carcass yield was, on average, 49% with no difference between weight classes (p > 0.05). The yield of posterior thighs was significantly higher for the lower weight class, which also presented higher percentage of paws (28.37 [+ or -] 0.63 and 9.33 [+ or -] 0.21, respectively) (p < 0.05). The percentages of visceral fat and skin showed a progressive increase along with the weight of the animals; the class with individuals weighing 201-250 grams showed the higher values (p < 0.05). The chemical composition indicated that individuals above 251 grams showed lower values of ether extract and higher values of crude protein (0.99 [+ or -] 0.14 and 15.80 [+ or -] 0.64, respectively) (p < 0.05). So, it is recommended the slaughter of bullfrogs weighing more than 201 grams, because of better yield and meat quality. Keywords: exotic species, meat processing, raniculture. O objetivo do trabalho foi comparar cinco diferentes classes de peso de ra-touro (Lithobates catesbeianus), buscando definir o peso ideal de abate para a especie. Foram utilizados 79 exemplares de ras-touro, distribuidas em um delineamento inteiramente casualizado (classe 1 251 g (n = 14)), que foram eutanaziados, pesados e eviscerados. Para o rendimento da carcaga foram pesados: tronco limpo, coxas, figado, patas, pele e cabega. O tronco limpo foi submetido a analise de composigao centesimal. O rendimento de corpo limpo foi em media 49%, sem diferenga entre classes (p > 0,05). O rendimento das coxas posteriores foi significativamente maior para a menor classe de peso, e essa classe tambem apresentou maior porcentual de patas (28,37 [+ or -] 0,63 e 9,33 [+ or -] 0,21, respectivamente) (p < 0,05). As porcentagens de gordura visceral e pele apresentaram um aumento progressivo concomitante ao peso dos animais, send