Insulin‐like growth factor‐I, passive immunity transfer, and stereological characteristics of small intestine of newborn calves

Abstract

This study evaluated the concentration of insulin‐like growth factor (IGF)‐I present in the mammary secretions, its relation with changes in serum IGF‐I and immunoglobulin (Ig)G, and intestinal mucosa alterations of 42 calves during the first week of life. Cows were randomly assigned to two groups, treated and control, with 21 animals in each. The treated group was injected with 500 mg recombinant bovine somatotropin (rbST) at day −35 relative to predicted calving date. Newborn calves were randomly assigned to a 2 × 3 factorial scheme: dams group and slaughter date (at birth, 2 and 7 days of life). IGF‐I concentration was higher in the colostrum of treated cows (P < 0.05), but did not differ in the subsequent mammary secretions. Immunoglobulin G concentration in colostrum and subsequent mammary secretions did not differ between groups (P > 0.05). No differences were found in calf serum IGF‐I levels from birth to the seventh day or serum immunoglobulin G concentration after 24 h of life (P > 0.05). IGF‐I colostrum levels observed in this study did not affect the small intestine morphometry. The segment from the middle jejunum showed higher mucosa partial volume (Vv) at birth and 7 days old compared to other segments, and at just 2 days of age this segment reduced its Vv, not differing from other segments of the same date.

Intestinal histology of newborn goat kids fed lyophilized bovine colostrum

“…Similar results were found in villi density in goat kids fed goat or lyophilized bovine colostrum (Moretti et al, 2012a). Corroborating these results, Bühler et al (1998) and Pauletti et al (2007) did not find changes in the intestinal morphometric characteristics of calves ingesting different amounts of IGF-I.…”

“…The enteric and absorptive capacity could be related with villus height, volume and density of the mucosa surface. As verified by Pauletti et al (2007) in calves and Van Ginneken et al (2002) in pigs, the jejunum showed the highest Vv, probably because of the highest villus or more numerous structures compared to other intestinal segments. A correlation between the villus height and Vv was verified (r = 0.72), suggesting a reflection about the capacity of the absorptive mucosa area.…”

“…In this study, the Sv was unaffected by different sources of colostrum, goat or lyophilized bovine, indicating that despite the increase of mucosal layer volume, the absorptive area per mucosa unit remains the same. Differences in absorptive mucosa area and intestine development are related with intense absorption of macromolecules and total solids obtained from colostrum, presence of villus with varying sizes, different stages of maturity enteric, and changes in rates of nutrient transport by the absorptive Ouvir cells (Pácha, 2000;Bessi et al, 2002a;Van Ginneken et al, 2002;Pauletti et al, 2007;Machado-Neto et al, 2011).…”

“…Thus, this lacteal secretion is important to newborn survival, influencing the intestine development and is responsible for providing, in addition to immunoglobulin, significant amounts of nutrients, hormones, and bioactive factors, such as insulin-like growth factor-I (IGF-I) (Bühler et al, 1998;Kráčmar et al, 1999Kráčmar et al, , 2004Blättler et al, 2001;Křenková and Čanderle, 2001;Blum and Baumrucker, 2002;Pauletti et al, 2007;Kindlein et al, 2008;Penchev Georgiev, 2008a, b). The intake of these growth factors is related to growth and maturation of the intestinal epithelium that influences the rate of epithelial cell renewal, as well as digestive and absorptive functions (Hammon and Blum, 2002;Kelly and Coutts, 2000;Blum and Baumrucker, 2002).…”

“…During the period of passive immunity acquisition, first 24-48 h of life, the ruminants' gastrointestinal tract has special characteristics that allows immunoglobulin uptake from colostrum (Bessi et al, 2002a, b;Pauletti et al, 2007;Kindlein et al, 2008). Thus, this lacteal secretion is important to newborn survival, influencing the intestine development and is responsible for providing, in addition to immunoglobulin, significant amounts of nutrients, hormones, and bioactive factors, such as insulin-like growth factor-I (IGF-I) (Bühler et al, 1998;Kráčmar et al, 1999Kráčmar et al, , 2004Blättler et al, 2001;Křenková and Čanderle, 2001;Blum and Baumrucker, 2002;Pauletti et al, 2007;Kindlein et al, 2008;Penchev Georgiev, 2008a, b).…”