Dependent on dietary treatments of mothers, rats showed individual preference of diets containing ingredients produced with different cultivation strategies

Summary

Three diets were prepared with ingredients cultivated by each of three different farming systems, low input of fertilizer without pesticides (LIminusP), low input of fertilizer and high input of pesticides (LIplusP), and high input of fertilizer and high input of pesticides (HIplusP). A preference test was conducted to investigate whether rats could distinguish among the three iso-energetic and iso-nitrogeneous diets, and the influence of the mothers’ diet was accordingly studied with regard to the food choice of the progeny. The experimental diets contained potatoes, carrots, peas, green kales, apples, and rapeseed oil and were formulated to meet the NRC requirements for growing rats by mixing. Rats were weaned from dams, which had been fed one of the experimental diets. For five days, rats (n=27) had free access to each of the three diets, and consumption of each of the diets was recorded daily. Thereafter, rats were offered a standard laboratory chow until the test was repeated. The results indicated that the majority of the rats showed individual preference for the diets and behaved similarly on different experimental days ( = 0.63 in repetition 1 and  = 0.73 in repetition 2) and in the two repetitions (τ = 0.79). There was a significant interaction between diet choice and mothers’ diet (P =0.04 in repetition 1 and P =0.05 in repetition 2): when mothers’ diet was LIminusP, the LIminusP was among the preferred diets. However, when the mothers were fed LIplusP or HIplusP, the rats showed the lowest consumption of LIminusP.