Growth, Metabolic and Adrenocortical Effects of Single and Repeated Administration of Diazepam in Piglets

Dvorak M.: Growth, Metabolic and Adrenocortical Effects of Single and Repeated Administration of Diazepam in Piglets. Acta vet. Brno, 49, 1980: 177-186. Diazepam was injected as a single i/m dose to suckling piglets of two groups on the 2nd day after birth at 0.5 or 1.0 mgjkg body mass. In two other groups of pigs weaned at 4 weeks of age it was injected at 0.5 mgjkg body mass or fed for 14 days in feed medicated at 8 mg/kg after weaning. The tranquilizing effect was substantially more intense in newborn than in weaned piglets. A rise in relative liver mass was found only in newborn animals 2 hours after diazepam administration. The adrenocortical function of the experimental animals proved unaffected, but their plasma Ll-hydroxycorticcsteroid level showed a downward trend, compared to controls. Total plasma protein, glucose, urea, free fatty acid and cholesterol concentrations were not affected. The growth performance of piglets injected on the 2nd days after birth was:not impaired: their growth expressed in terms of total gain in body mass from birth to weaning was 6.8 per cent higher than that of their untreated littermates. Similarly, piglets fed diazepam-medicated feed at an average of 0.35 mg/kg body mass for 14 days after weaning gained 21 per cent more than the controls. Their feed consumption was practically the same as in the controls, but their feed conversion efficiency was better. Not all diazepam-medicated piglets showed signs of tranquilization. The alleviation of stress as suggested by blockade of the circulating corticosteroid increase during handling of the animals and the other results indicate the usefulness of diazepam as tranquilizer in pigs. Tranquilization, stress, neonatal influences, development, pig. A number of handlings of newborn animals have been reported to influence their further somatic development and function of some organs. These effects have been studied mainly in laboratory animals and some of them were confirmed in piglets (Dvorak 1980). Similarly, drugs administered during the gestation and perinatal period may affect further development of the offspring. Besides adverse side-effect, they may have favourable sequelae. For example, phenobarbital was reported to stimulate the hepatic enzyme system metabolizing foreign substances in foetuses and young animals (Kuenzig et a1. 1975). Psychoactive drugs deserve attention also in view of their possible effects on postnatal neural development and later behaviour of the animals (Sparber 1972; Middaugh et a1. 1975; Dorner 1976). Neonatal administration of chlorpromazine to mice increased endocrine and spermatogenic function of the testes (Hogarth and Chalmers 1973). On the other hand, diazepam treatment of rats cancelled the majority of late androgenic effects of neonatal stress (Brd osova et al, 1975). Diazepam (7-chloro-l,3-dihydro-l-methyl-5-phenyl-2H-l,4-benzodiazepin-2-one) finds wide application in human medicine because of its anxiolytic, anticonvulsive and myorelaxant effects. I t is also used in treating animals, particularly as tranquilizer administered to pigs before regrouping and transport (Drumew et a1. 1972; Kolacz and Pejsak 1975; Dantzer 1977; Leistner 1978). In contrast to neuroleptics it has the advantage, together with other anxiolytics, tha t it can block, depending on dosage, the rise in plasma corticosteroid level occurring in stress (La hti and