The Effect of Undernutrition and Rehabilitation on the Development of the Reproductive Organs: Pigs

Abstract

1) During prolonged undernutrition in pigs from 2 to 3 weeks of age: (a) the tubules of the testes developed but the interstitial cells regressed and became unrecognizable; (b) the glans penis became large and oedematous; (c) the primordial follicles in the ovaries developed and some became large and cystic but ovulation did not follow; (d) the uterus and vulva enlarged.(2) During rapid rehabilitation: (a) The vulva and testicles became much enlarged relative to the rest of the body; (b) the glans penis developed but the oedema disappeared and was replaced by collagen and cellular material; (c) the female animals did not ovulate until they were approaching the body weight at which ovulation normally occurs; (d) the seminiferous tubules of the testes showed active spermatogenesis when the animals were still relatively small but the interstitial cells did not reappear until later.

Compensatory growth and sexual maturity in broiler females reared under severe food restriction from day of hatching

“…Such a requirement may be the explanation for the well documented observation that the greater the degree of food restriction in poultry (and hence the lower the body weight at the end of the restriction period), the longer the delay in egg production when food restriction ceases (Lee et al, 1971). Data which can be interpreted similarly have been reported for cattle (Crichton et al, 1959), pig (Dickerson et al, 1964), rat (Kennedy and Mitra, 1963) and human (Frisch and Revelle, 1970).…”

Body weight and/or fatness as potential determinants of the onset of egg production in broiler breeder hens

“…Undernutrition may produce a distortion of the normal growth pattern, with some parts of the body having priority of growth over others, and with some body functions appearing only after the attainment of a certain size. In pigs this is true for the production of luteinising hormone (Dickerson et al, 1964), and in chickens, too, the secretion of this hormone, which is essential for ovulation, may be linked with the attainment of a particular size (Buonomo et al, 1982). It should be emphasised, however, that no proof has been offered in this study that body weight is a causal factor rather than only a correlate of the start of lay, nor has the mechanism been determined by which weight influences or initiates the onset of egg production.…”

Effects of age and live weight on the sexual development of gilts and boars fed two planes of nutrition

“…Cervix weight and length increased (P < 0.01) to a lesser extent ( x 1.4 and x 1.2, respectively) after puberty. (Joshi and Raeside, 1973 ;Morat et al 1980 ;Booth, 1980Booth, , 1983Lauwers et al, 1981) and undernutrition is known to reduce androgen production (Dickerson et al, 1964 ;Bonneau, 1987 (1983). However, the growth performances in the study of Den Hartog and Noordewier (1984) were similar to ours, while in that of Etienne et al (1983) gilts fed ad libitum had a slower growth rate so that they were one month older at 125 kg of live weight.…”