HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Greenwood, P. L. Articles by Bell, A. W. Search for Related Content PubMed PubMed Citation Articles by Greenwood, P. L. Articles by Bell, A. W.

Effects of birth weight and postnatal nutrition on neonatal sheep: IV. Organ growth^1,2

Department of Animal Science, Cornell University, Ithaca, NY 14853-4801

⁶ Correspondence—phone: 607-255-2862; fax 607-255-9829; e-mail: awb6{at}cornell.edu.

Abstract

This study investigated effects of birth weight and postnatal nutrition on organ growth in neonatal lambs. Suffolk x (Finnsheep x Dorset) low- (mean ± SD 2.29 ± 0.34 kg, n = 28) and high- (4.84 ± 0.45 kg, n = 20) birth-weight male lambs were studied. Lambs within each birth weight category were allocated to be individually grown rapidly (ad libitum fed, ADG 337 g, n = 20) or slowly (ADG 150 g, n = 20) on a liquid diet to live weights up to approximately 20 kg. All organs weighed less at birth in small than in large newborns (P < 0.001), except the adrenals (P = 0.10). At birth, as a percentage of empty body weight (EBW), small newborns had larger testes (0.14 vs. 0.10%, P = 0.023) and smaller thymus (0.17 vs. 0.37%, P = 0.009), and tended to have a larger heart (0.85 vs. 0.75%, P = 0.060) and a smaller spleen (0.10 vs. 0.14%, P = 0.054) than large newborns. During the first 2 to 3 wk postpartum, small newborns had greater fractional growth rates of organs than large newborns, most notably spleen, thymus, and liver. Postnatal growth of organs was more closely associated with EBW than age, except for lungs, testes, and stomach. At completion of rearing to 20 kg of live weight, small newborns had a spleen approximately 30% heavier than large newborns (P < 0.001). Testes weights were 37% and 24% greater in small newborns reared slowly and rapidly, respectively, compared with their high-birth-weight counterparts (P = 0.034). It was also evident that postnatal nutrition altered the mass of individual organs at the conclusion of the rearing period without affecting the combined weight of dissected organs. Slowly reared lambs had a larger pancreas (+27%, P = 0.002), stomach complex (+83%, P < 0.001), large intestine (+39%, P < 0.001), entire gastrointestinal tract (+18%, P = 0.002), and testes (+54%, P = 0.016) and tended to have a larger heart (+6%, P = 0.068) than their rapidly reared counterparts at 20 kg of live weight. Rapidly reared lambs had a larger thymus (+61%, P = 0.003), liver (+34%, P < 0.001), kidneys (+33%, P < 0.001), and small intestine (+17%, P < 0.001) and tended to have a larger thyroid (+13%, P = 0.054) at 20 kg of live weight than slowly reared lambs. The functional significance of the smaller thymus at birth and increase in spleen and testes weights at 20 kg of live weight in low- compared with high-birth-weight lambs warrants further investigation. It also remains to be established whether these differences at 20 kg of live weight persist.

Key Words: Birth Weight • Growth • Lambs • Nutrition • Organs

This article has been cited by other articles:

				I. Tzoulaki, M.-R. Jarvelin, A.-L. Hartikainen, M. Leinonen, A. Pouta, M. Paldanius, A. Ruokonen, D. Canoy, U. Sovio, P. Saikku, et al. Size at birth, weight gain over the life course, and low-grade inflammation in young adulthood: northern Finland 1966 birth cohort study Eur. Heart J., April 9, 2008; (2008) ehn105v1. [Abstract] [Full Text] [PDF]