Age, sex, and weight at weaning influence organ weight and gastrointestinal development of weanling pigs

Abstract

The present study was designed to determine the interrelationships between sex, weaning age, and weaning weight on aspects of physiological and gastrointestinal development in pigs. Forty-eight Large White × Landrace pigs were used in a factorial arrangement with the respective factors being: age at weaning (14 or 28 days), weight at weaning (heavy or light), sex (boar or gilt), and time after weaning (1, 7, and 14 days). At weaning, 48 pigs were removed from the sow: 16 pigs were then fasted for 24 h before euthanasia for determination of organ weights, gut histology, and enzymology, and 32 pigs were offered a high quality pelleted weaner diet ad libitum for subsequent assessment of organ weights, histology, and enzymology at 7 and 14 d after weaning. On Day 6 and 13 after weaning, 2 pigs from each group had their feed removed, and 24 h later were euthanased and similar measurements were taken. In general, the data highlighted the overall gastrointestinal underdevelopment of pigs weaned at 2 weeks of age and of pigs weaned light-for-age at either 2 or 4 weeks. Heavier body organs, gastrointestinal organs, and accessory digestive organs observed after weaning, except for the spleen, presumably reflected the increase in substrates available for cellular growth as feed intake increased after weaning, and the development of organs required to process this feed. Interestingly, the relative weights (% of liveweight) of the stomach and small intestine and, to a lesser extent, the caecum and colon, were greater in the light, 14-day-old weaned pigs, but these differences diminished with increasing time after weaning. Consistent effects due to age, weight, and sex were not observed for villous height and crypt depth, or for the specific activities of the brush-border and pancreatic enzymes measured. However, increases (P < 0.001) in the activities of maltase (P�<�0.001), glucoamylase (P < 0.001), and sucrase (P = 0.020) (all expressed per gram of mucosa), and that of trypsin (per gram of pancreas), occurred by 14 days after weaning. This most likely reflected the inducible nature of these enzymes in response to the increasing intake of substrates provided in the diet. In contrast, the specific activity of lactase declined (P = 0.012) in the first 14 days after weaning. These data suggest that pigs weaned at 2 weeks of age and pigs weaned light-for-age at either 2 or 4 weeks have a less developed gastrointestinal tract, and that its development after weaning might proceed differently to that of pigs weaned older and heavier.

Comparison of total tract digestibility, development of visceral organs and digestive tract of Mong cai and Yorkshire × Landrace piglets fed diets with different fibre sources

“…The influence of fibre level and fibre source in the diet on the development of the visceral organs and GIT of growing pigs in general and of piglets in particular has been documented in a number of reports which showed that pigs fed high‐fibre diets had heavier weight of GIT than those given a low‐fibre diet (Jørgensen et al.,1996a; Nyachoti et al., 2000; Freire et al., 2003; Pluske et al., 2003) which is in agreement with the results of the present study. However, the effect varied between fibre sources because of the different fibre components, for example, the ratio of soluble/insoluble fibre (Bach Knudsen and Jørgensen, 2001).…”

“…In the present study, the absolute weight of visceral organs and GIT increased with piglet age. However, when expressed as g/kg EBW, the weight of visceral organs decreased with age, which is in agreement with Pluske et al. (2003), who found that the relative weight of the visceral organs of piglets had a tendency to decrease between 14 and 28 days of age.…”

“…In agreement with a previous study (Cera et al., 1988), the mass specific weight of the GIT increased more rapidly during post‐weaning than in the pre‐weaning probably, as a result of feeding high‐fibre diets to the piglets in post‐weaning in the present study. A similar finding was reported by Pluske et al. (2003), who found that the relative weight of the GIT of suckling piglets not given access to solid feed had a tendency to decrease with age before weaning, but increased after weaning when solid feed was provided.…”

Invited review: Aspects of gastrointestinal tract growth and maturation in the pre- and postweaning period of pigs

“…All components and accessory organs of the GIT are influenced by weaning, irrespective largely of weaning age; however, because of its size and biological importance, it is the small intestine that is affected the most and has to make the greatest anatomical, physiological, and immunological adaptation to changes in the pattern and form of feed consumption, changes in dietary substrates, and adjustment to stress (e.g., Stokes et al, 1994;Cranwell, 1995;Xu, 1996;Pluske et al, 1997;Zabielski et al, 1999;Burrin and Stoll, 2003;Pluske et al, 2003;Boudry et al, 2004;Lallès et al, 2004;Burkey et al, 2009;Wijtten et al, 2011Wijtten et al, , 2012Pluske, 2013). It is simply beyond the scope of this review to summarize all the changes to the GIT that occur in the periweaning period, with a plethora of authors having already described the rapid and consistent changes to structure (e.g., villous height and crypt depth, size and shape, tight junction integrity) and function (e.g., digestive and absorptive activity and capacity, loss of surface area, inflammation, antioxidant capacity) that occur in the acute and adaptive phases of growth in the periweaning period (Fig.…”

Diet nutrient digestibility and growth performance of weaned pigs fed field pea

“…Although pulse protein can replace specialty protein feedstuffs in diets for weaned pigs, digestion of protein in raw field pea might be a concern for pigs immediately after weaning due to a less-developed digestive system (Pluske et al, 2003;Lalles et al, 2007;Gunawardena et al, 2010b). The storage protein in field pea is mainly globulin, e.g., legumin and vicilin (Boulter, 1983).…”