Growth differences of male and female Göttingen minipigs during ad libitum feeding: a pilot study.

Even though minipigs have been used in biomedical research for nearly half a century now, no specific nutrient requirements are available. For that reason a series of studies into the nutrient requirements of Göttingen minipigs were carried out. Firstly, a pilot study was carried out to determine the ad libitum feed intake (FI) during growth, as a reference for later feed restriction studies. Four male and four female minipigs were fed two types of diet, one standard pig diet (20.6% crude protein; 11.7% crude fat; 13.5 mJ/kg DM metabolizable energy) and one diet specially designed for minipigs (12.0% crude protein; 2.9% crude fat; 11.9 MJ/kg DM metabolizable energy). When fed ad libitum for 13 weeks, female Göttingen minipigs developed a significantly (P<0.05) higher body weight (BW) than males (27.4 vs 16.6 kg) on either diet. The large difference in growth between male and female Göttingen minipigs did not appear to be the result from differences in metabolizable energy intake. Metabolizable energy intake of male and female Göttingen minipigs could be predicted by ME=1877 kJxBW(0.61). Both male and female Göttingen minipigs became obese when fed ad libitum, defined by relative backfat thickness. Relative backfat thickness ranged from 5 to 13 cm/100 kg. Females had thicker relative backfat layers than males. Remarkably, no large changes in haematology and clinical chemistry occurred in ad libitum fed Göttingen minipigs as compared to reference values, and no abnormalities other than enlarged fat reserves were observed at necropsy. Apparently, Göttingen minipigs do not restrain FI voluntarily, and restricted feeding is therefore indicated to prevent obesity.

Non-invasive method for sampling and extraction of mouse DNA for PCR.

We adapted a non-invasive, fast, reliable and inexpensive procedure for the sampling and extraction of deoxyribonucleic acid (DNA) for genetic testing of mice. The procedure is based on a simple DNA extraction procedure used in the forensic genetic testing of humans. It involves mouth swabbing of the inner cheek using a cotton stick, followed by alkaline lysis of the harvested buccal epithelial cells. This procedure allows for repeated sampling and genetic testing of the individual mouse, and it is faster, simpler and, in our hands, more reliable than the currently used routine procedures for the sampling and extraction of mouse DNA. Current procedures all involve biopsy of a piece of the tail, ear or toe, followed by lengthy procedures to release and isolate the DNA.