Lactate, propionate and butyrate induced morphological alterations on calf ruminal mucosa and epidermis. / AlteraÃÃes morfolÃgicas induzidas por Butirato, Propionato e Lactato sobre a mucosa ruminal e epiderme de bezerros

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

Volatile fatty acids (VFA) may cause morphological alterations on bovine keratinized stratified epithelial tissues. The objective was to evaluate the effect of butyrate, propionate and lactate on ruminal wall, the epidermis of nasolabial surface, the perioplum and the epicera of calves. Also, to validate the procedure and interpretation of tegument biopsies as indicators of ruminal mucosa alterations. Ruminal activity on 17 neonatal calves was lowered by continuous liquid diet. At 45 days of age foley catheters were placed surgically in the rumen. Daily infusions were 0.0744 and 0.0636 moles/kg of metabolic weight for propionate and butyrate, and lactate, respectively. Serum insulin was sampled on the 22nd day from the beginning of treatments at, 0, 90, 180 and 360 minutes relative to the morning infusion. After slaughter tissue samples were collected from ruminal cranial sac, recess and caudo-ventral sac, nasolabial surface, epicera and perioplum from front and hindquarters. All VFA induced greater increase on ruminal-reticulum proportionate weight than on omasum. Butyrate was a greater stimulator of non-glandular stomach growth than lactate and butyrate. VFA infusion tended to increase weight and proportion of ruminal cranial sac epithelium and sub epithelial stroma, however they reduced papillae number per ruminal wall square centimeter. Although butyrate stimulated more insulin secretion, this VFA was not capable to induced gain on papillae area or height. Although VFA infusion increased metabolically active ruminal cell area, only propionate tended to increase ruminal cranial sac papillary area. Cellular mitosis response to lactate and butyrate infusion seemed to have occurred in response to induced VFA induced rumenitis. Nasolabial surface VFA infusion effect was the opposite to that observed in the rumen. VFA increased hind perioplum mitotic index, contrary to its effect on the nasolabial surface and epicera. No histopathological lesions were observed on nasolabial surface, epicera and perioplum, demonstrating that these are consequences of VFA direct effect on ruminal epithelium. Butyrate and lactate were better pathological alterations inducers on the ruminal epithelium. VFA effects on ruminal mucosa morphology and on other keratinized tissues suggest that morphological damage on hoof and ruminal epithelium may have a common cause, which explains the simultaneous anomaly occurrence on these structures from cattle subject to ruminal acidosis. Tegumentary biopsies may be useful as ruminal mucosa morphological alteration indicators.

ASSUNTO(S)

perioplum plano nosolabial zootecnia epicera nasolabial surface ultraestrutura perioplum volatile fatty acids epicera ultrastructure Ãcidos graxos volÃteis

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