Potential stock differences in the social behavior of rats in a situation of restricted access to food

Abstract

The social behavior of outbred Long-Evans (LE) and Wistar (WI) rats was compared in a situation where access to food was particularly difficult (clearing an aquatic barrier, plus the necessity of carrying the food back to the home cage). In groups of either six WI or LE rats, only about 50% of individuals carried the food, and the others survived by attacking those that did. However, behavioral profiles associated with these acts were different in the two cases: LE carriers, contrary to WI carriers, restole some food, and LE noncarriers expressed more agonistic behavior and were more often attacked than were the WI noncarriers. Food flow and all associated, interactive behaviors were more complex in the LE than in the WI rats, indicating the likelihood of potential genetic differences in this testing situation.

Long-term effects of early diazepam exposure on social differentiation in adult male rats subjected to the diving-for-food situation.

“…The results of this study showed that a social differentiation appeared in all groups of rats exposed to the diving-for-food situation, each group being composed of an equal number of vehicle- and DZ-treated rats. The respective proportions of carriers and noncarriers were very close to 50%, which was consistent with previous studies (Colin & Desor, 1986; Helder et al, 1995; Krafft et al, 1994; Thullier et al, 1992). As previously shown (Schroeder, Collignon, et al, 1994; Schroeder, Humbert, Desor, & Nehlig, 1997; Schroeder, Humbert, Koziel, et al, 1995), early DZ treatment induced a loss of weight at the adult stage.…”

“…The apparatus used was described in previous articles (Colin & Desor, 1986; Helder et al, 1995; Krafft et al, 1994; Thullier et al, 1992). It consists of a home cage (40 × 40 × 40 cm) linked to an aquarium (150 × 25 × 40 cm) by a tunnel.…”

“…Social interaction tests (File, 1980, 1985) or social competition tests (Gentsch, Lichtsteiner, & Feer, 1988; Joly & Sanger, 1991) are particularly sensitive and selective procedures for detecting and evaluating the level of anxiety and the actions of anxiolytic drugs. The diving-for-food situation allows the study of social relations of rats, which strongly interact to get food (Helder, Desor, & Toniolo, 1995; Krafft, Colin, & Peignot, 1994; Thullier, Desor, Mos, & Krafft, 1992), and may represent a potent test for the investigation of the anxiolytic effects of pharmacological treatments.…”