Moderated milk replacer restriction of ewe lambs alters gut immunity parameters during the pre-weaning period and impairs liver function and animal performance during the replacement phase

Abstract

Undernutrition during the first stages of life may impair maturation of the immune system, harming the health status permanently. Thus, the aim of the present study was to define the impact of moderated milk replacer (MR) restriction during the artificial rearing period on the gut-associated lymphoid tissues of pre-weaned ewe lambs and long-term effects on biochemical profile and animal performance during the replacement period. Forty female Assaf lambs [average live body weight (LBW) 4.73 ± 0.116 kg] were penned individually. The first group of lambs (n=20) was fed MR ad libitum (ADL) whereas the second one (restricted, RES; n=20) only received approximately 62.5% of the MR intake measured in the ADL group. All the lambs were weighed twice a week until they were 35-days-old. Then, 8 lambs from each group (preweaned) were harvested and ileal samples collected. The rest of the lambs (12 ADL vs. 12 RES) were weaned progressively, and then offered a total mixed ration (TMR) ad libitum until the end of the experiment (7.5-months-old). The lower nutrient intake of RES pre-weaned lambs caused greater percentages for T lymphocytes (CD4 + , CD8 + , WC1 +) and an increased secretory immunoglobulin A (sIgA) production in the ileum compared to the ADL group (P<0.05). These results, together with the significant differences in the expression of toll-like receptors and cytokines at this level (e.g., interferon gamma was increased in the RES group; P<0.05) suggest the existence of pro-inflammatory conditions in the ileum of pre-weaned lambs promoted by early feed restriction. Moreover, the biochemical profile revealed that liver function (e.g., albumin, gamma glutamyl transpeptidase) was impaired during several months once the feed restriction period was finished, whereas the average daily gain during the replacement phase was reduced for the early feed restricted lambs (182 vs. 202 g/day for RES and ADL groups, respectively; P<0.05). Therefore it can be concluded that moderated MR restriction promoted both, pro-inflammatory conditions at ileal level in the pre-weaned lambs and an altered liver function which lasted several months after the end of feed restriction. Both circumstances might have impaired animal performance during the replacement phase of the ewe lambs.

Liver transcriptomic and proteomic profiles of preweaning lambs are modified by milk replacer restriction

“…Regarding lambs, several studies have shown that metabolic programming events are caused by early feed restriction (Davies and Owen, 1967;Greenwood et al, 2004;Galvani et al, 2014), with negative long-term effects after the period of feed restriction. In this sense, previous studies have demonstrated negative consequences not only on the health status (Frutos et al, 2018) and feed efficiency traits (Santos et al, 2018c,d), but also on the onset of puberty in replacement ewes lambs (Santos et al, 2018c). However, even though we have found several studies in children (Ruchat et al, 2014), cattle (Soberon et al, 2012;Soberon and Van Amburgh, 2013;Alexandre et al, 2015), and pigs (Vincent et al, 2015), to our knowledge no studies have described the effects of early feed restriction at the gene expression level in artificially reared female Assaf lambs.…”

“…Accumulated MR intake and animal performance of these preweaning lambs selected for omics (8 preweaning lambs in total) are summarized in Table 2 and Figure 1, whereas the rest of parameters measured at slaughter (16 preweaning lambs in total) are described in Santos et al (2018c). The nonslaughtered animals (24 lambs in total) were weaned and fed ad libitum a TMR to study the effects of metabolic programming provoked by early feed restriction during the replacement phase (Frutos et al, 2018;Santos et al, 2018c). In the present study, only those data regarding liver transcriptomic and proteomic profiles of preweaning lamb (those slaughtered) are presented.…”

Programación metabólica de la eficiencia alimentaria en corderos: efecto de la restricción de alimento en la etapa de lactancia y mecanismos moleculares implicados = Metabolic programming of lamb feed efficiency: effect of feed restriction during the suckling period and molecular mechanisms involved

“…Regarding lambs, several studies have shown that metabolic programming events are caused by early feed restriction , with negative long-term effects after the period of feed restriction. In this sense, previous studies have demonstrated negative consequences not only on the health status (Frutos et al, 2018) and feed efficiency traits (Santos et al, 2018c,d), but also on the onset of puberty in replacement ewes lambs . However, even though we have found several studies in children , cattle Soberon and Van Amburgh, 2013;, and pigs , to our knowledge no studies have described the effects of early feed restriction at the gene expression level in artificially reared female Assaf lambs.…”

“…Accumulated MR intake and animal performance of these preweaning lambs selected for omics (8 preweaning lambs in total) are summarized in Table 2 and Figure 1, whereas the rest of parameters measured at slaughter (16 preweaning lambs in total) are described in . The nonslaughtered animals (24 lambs in total) were weaned and fed ad libitum a TMR to study the effects of metabolic programming provoked by early feed restriction during the replacement phase (Frutos et al, 2018;. In the present study, only those data regarding liver transcriptomic and proteomic profiles of preweaning lamb (those slaughtered) are presented.…”

“…Esto podría ser consecuencia de una menor formación de amoniaco en estos animales al haber menos sustrato disponible, o bien de un aumento en la proporción del amoniaco que es eliminado directamente, que reduciría el coste energético asociado con la síntesis de urea (Rodríguez et al, 2007;Cruzen et al, 2013). No obstante, estas diferencias en los niveles plasmáticos de urea no se mantuvieron a los 5 y a los 7,5 meses de edad (durante el 2º periodo posdestete) (Frutos et al, 2018a), lo que sugiere que estos cambios adaptativos desaparecen a largo plazo, una vez que la alimentación se ha reestablecido con normalidad.…”