Os objetivos deste trabalho foram determinar a funcionalidade do sulco do retículo em bovinos adultos e avaliar técnicas alternativas para preparação, infusão e coleta de marcadores da dinâmica ruminal. Quatro vacas com cânulas ruminais foram utilizadas em três ensaios experimentais. No ensaio 1 a porcentagem de água que passou diretamente ao omaso (27,39 %) tendeu a ser menor (P = 0,14) que a porcentagem de água que atingiu o ruminorretículo (72,61 %), indicando funcionamento ineficiente dessa estrutura em bovinos adultos. No ensaio 2, as taxas fracionais de passagem de fluido determinadas simultaneamente por Cr-EDTA (14,79 % h-1) e Co-EDTA preparado por técnica alternativa (14,76 % h-1) não diferiram (P = 0,96) e as regressões exponenciais tiveram alto coeficiente de determinação (r² = 0,90). A relação Co:Cr no fluido ruminal não diferiu ao longo das quatro horas de coleta de amostras (P = 0,68). Não houve variação entre a relação Co : Cr na urina e nas fezes. A técnica de fácil execução, proposta para preparação do Co-EDTA, mostrou-se efetiva. No ensaio 3, em que os marcadores foram infundidos à digesta sem homogeneização, a melhor plotagem (r² = 0,88; P < 0,001) da regressão exponencial foi obtida excluindo-se os cinco primeiros tempos de coleta (1,67 h após infusão) e dobrando-se os intervalos até as 5,33 h após infusão. Nesse padrão de coleta, os coeficientes de determinação das regressões exponenciais não diferiram (P = 0,17) de curvas padrões (r² = 1), quando comparados hipoteticamente. As técnicas alternativas propostas para infusão e amostragem são viáveis, mas requerem validação.

Absorption and metabolism of volatile fatty... 93Ciênc. agrotec., Lavras, v. 36, n. 1, p. 93-99, jan./fev., 2012 ABSORPTION AND METABOLISM OF VOLATILE FATTY ACIDS BY RUMEN AND OMASUM ABSTRACTVolatile fatty acids (VFA) absorption and metabolic capacity of rumen and omasum were compared, in vitro. Fragments of rumen wall and omasum laminae were taken from eight adult crossbred bovines. An isolated fragment of the mucosa was fitted in a tissue diffusion chamber. Valeric acid and CrEDTA were added to ruminal fluid and placed on the mucosal side and buffer solution was placed on the serosal side. Fractional absorption rates were measured by exponential VFA:Cr ratio decay over time. Metabolism rate was determined as the difference between VFA absorbed and VFA which appeared on the serosal side over time. Mitotic index was higher in omasum (0.52%) than in rumen epithelium (0.28%). VFA fractional absorption rate was higher in omasum (4.6%/h.cm 2 ) than in rumen (0.4%/h.cm 2 ). Acetate, propionate, butyrate, and valerate showed similar fractional absorption rates in both fragments. Percentage of metabolized acetate and propionate was lower than butyrate and valerate in both stomach compartments. In the rumen, individual VFA metabolism rates were similar (mean of 7.7 μ mol/h.cm 2 ), but in the omasum, valerate (90.0 μ mol/h.cm 2 ) was more metabolized than butyrate (59.6 μmol/h.cm 2 ), propionate (69.8 μ mol/h.cm 2 ) and acetate (51.7 μmol/h.cm 2 ). Correlation between VFA metabolism and mitotic index was positive in the rumen and in the omasum. In conclusion, VFA metabolism and absorption potential per surface of the omasum is higher than that of the rumen. Variations on rumen and omasum absorption capacities occur in the same way, and there are indications that factors capable of stimulating rumen wall proliferation are similarly capable of stimulating omasum walls.Index terms: Morphology, physiology, bovine, ussing chamber, forestomach. RESUMOA capacidade de absorção e metabolismo de ácidos graxos voláteis (AGV) pelo rúmen e omaso foi comparada, in vitro. Fragmentos da parede do rúmen e das lâminas do omaso foram coletados de oito bovinos mestiços adultos. Um fragmento isolado da mucosa foi colocado em uma câmara de difusão tecidual. Ácido valérico e CrEDTA foram adicionados ao fluido ruminal e colocados no compartimento da câmara voltados para a mucosa e uma solução tampão foi colocada no compartimento voltado para a serosa. As taxas fracionais de absorção foram medidas pela queda exponencial da relação VFA:Cr ao longo do tempo. A taxa de metabolismo foi determinada pela diferença entre a quantidade de AGV absorvida e a detectada no compartimento serosal da câmara. O índice mitótico foi mais alto no epitélio do omaso (0.52%) do que no do rúmen (0.28%), bem como a taxa fracional de absorção, 4.6%/h.cm 2 e 0.4%/ h.cm 2 , respectivamente. Acetato, propionato, butirato e valerato tiveram taxas fracionais de absorções similares em ambos os compartimentos. As porcentagens do acetato e do propionato metabolizados foram ...

The Brazilian tannery industry produces annually an enormous amount of scraps and leather shavings impregnated with chromium due to the tanning process. Technologies have been developed to remove chromium from this material. The resultant residue from the chromium removal process is high in protein with a high digestibility, suggesting that this residue may be used to feed monogastric animals. However, due to the nature of this residue, there is a risk of chromium poisoning and the introduction of botulism. The aim of this work was to establish the risks of adding tannery residues to animal feeds, using rats as an experimental model. Forty-eight Wistar rats were placed under eight treatments in a 2 by 4 factorial arrangement. The rats were fed over 60 days with a standard AIN-93 diet and the treatments consisted of replacing part of the diet with 0, 25, 37.5 or 50% of the chromium-tanned leather residue, in natura, known as ‘wet blue’, or the same percentages of this residue after chromium extraction. Industrial processing was able to remove 70–80% of the chromium from the residue. This high chromium level had a negative effect on the weight gain of the animals and caused lesions in the kidneys especially due to the chromium extraction material, suggesting that the removal process increases the biological activity of chromium, making it nefrotoxic. The gravity of this effect was directly proportional to the inclusion level. The results of this study indicate that until industrial processing is refined so that more of the chromium residue is removed, the use of the tannery residues in animal feeds is not safe.

Cannulated cows were allocated to a cross-over design to evaluate the technique for determination of volatile fatty acid (VFA) clearance by infusion of marker solution into intact ruminal digesta, and verify the technique sensibility to the variation in the diet. Animals received diet of forage or forage plus concentrate and infusion of valeric acid and Cr-EDTA solution into intact or evacuated ruminal digesta. The total fractional rate of VFA clearance (FRVFAC) was estimated by the exponential decay of valerate over time. The passage FRVFAC to the omasum was assumed as the decay in ruminal Cr concentration and the absorption FRVFAC was estimated by the difference. The total FRVFAC and absorption did not differ between techniques. The passage FRVFAC, however, was lower when the marker solution was added into the evacuated digesta, probably reflecting the destabilization of the rumen environment during the evacuation and the largest volume of fluid observed in animals with evacuated digesta. In conclusion, the infusion of marker solution into intact digesta with homogenization performed by ruminal motility could be usable for the VFA ruminal clearance determination since it seems to cause lesser disturbance in the ruminal environment.

The name of the species tetradactyla means “four digits.” In the literature, the hand of the lesser anteater (Tamandua tetradactyla) is described as having four digits (I, II, III and IV) with the absence of a fifth digit. The purpose of this study was to carry out an update adequately proposing an anatomical description of the T. tetradactyla hand. The present findings were analysed on the validation of Morse’s law for this species. In total, seven male cadavers were radiographed and dissected. We observed that the hand of the T. tetradactyla was formed by a carpus containing four bones in the proximal row, which in the medium lateral direction was the radial, intermediate, ulnar and accessory bones of the carpus, and the distal row was formed by carpal bones I, II, III and IV. There were five metacarpal bones (I, II, III, IV and V). The presence of five digits was verified but not confirmed with the literature. Digit I had two phalanges, the proximal and distal; digits II, III and IV had three phalanges: proximal, middle and distal. Digit five had only one phalanx, the proximal, but it was not externally visible. According to the findings of this study, the presence of the fifth digit raises the question of whether the term tetradactyla is the most appropriate to describe this species. This rudimentary fifth digit and the presence of a functional first digit show that the Morse’s law does not applies for the T. tetradactyla species.