Concentrations of energy substrates in oviductal fluid and blood plasma of pigs during the peri-ovulatory period.

Large White gilts, 9 to 18 months old, that had exhibited at least two natural oestrous cycles were divided into three groups (phases): unmated pre-ovulatory, unmated post-ovulatory and mated post-ovulatory (n = 16, 20 and 18). Oviductal luminal fluid samples were collected under anaesthesia by micropipette from the ampulla and ampullary-isthmic junction and analysed by an ultramicrofluorometric technique. Glucose concentrations (mmol 1(-1), means combining regions; mean +/- SEM) were significantly higher in blood plasma than in oviductal fluid (4.56 +/- 0.20 versus 0.59 +/- 0.16; P < 0.0001; n = 27), whereas lactate was higher in the oviduct (5.71 +/- 0.53 versus 2.48 +/- 0.24; P < 0.0001; n = 27). No significant differences were found between the ampulla and the ampullary-isthmic junction. However, the concentration of glucose was significantly higher (P < 0.05) in the ampulla of the pre-ovulatory group (0.97 +/- 0.20; n = 13) compared with the mated group (0.25 +/- 0.05; n = 14) and its concentration in the ampullary-isthmic junction in the pre-ovulatory group (1.65 +/- 0.63; n = 13) was significantly greater (P < 0.05) than in the post-ovulatory (0.43 +/- 0.11; n = 11) or mated groups (0.17 +/- 0.02; n = 14). Lactate in the ampulla of mated animals was higher than in the pre-ovulatory group (6.83 +/- 0.70 versus 3.86 +/- 0.38; P < 0.05; n = 15 and 13), but neither was significantly different from the post-ovulatory group. Furthermore, no change was seen at the ampullary-isthmic junction in lactate concentration with phase.(ABSTRACT TRUNCATED AT 250 WORDS)