Effects of intranasal ZnSO4 irrigation are mitigated by the presence of untreated littermates.

Observable anomalies were produced in spiny mouse neonates and weanlings through intranasal irrigation with ZnSO4 solution. In comparison to control animals, ZnSO4-treated pups displayed growth retardation, increased mortality rates, hyperactivity in a novel environment and difficulty in finding hidden food pellets. Each of these experimentally-induced deficits was alleviated when treated pups were housed and tested in the presence of intact littermates. The early social environment exerts marked influences on behavioral and physiological development and, if optimal, can buffer pups from the adverse effects of early physical insults.