Effects of crude protein and lactose levels in diets on growth performance, intestinal morphology, and expression of genes related to intestinal integrity and immune system in weaned piglets.

To evaluate the effects of crude protein (CP) and lactose (LAC) for weaned piglets on performance, intestinal morphology, and expression of genes related to intestinal integrity and immune system, 144 piglets with initial weight 7.17 ± 0.97 kg were allotted in a randomized design, in a 2 × 3 factorial arrangement (20.0% and 24.0% CP and 8.0%, 12.0%, and 16.0% LAC) with eight replicates. Piglets fed 20.0% CP had greater weight gain and feed intake. Including 12.0% LAC in the 20.0% CP diet provided higher villous height in the duodenum than 8.0% LAC, and 12.0% or 16.0% LAC in the 24.0% CP diet resulted in higher villous height in the jejunum and ileum, and higher villi/crypt ratio in the ileum than 8.0% LAC. No effects of CP and LAC on interleukin-1ß and tumor necrosis factor-α mRNA were observed. The 16.0% LAC diet provided higher gene expression of transforming-ß1 growth factor. Feeding 20.0% CP resulted in better performance than 24.0% CP. The 12.0% LAC diet promoted greater genetic expression of occludin and zonula occludens. Including 12.0% LAC in the diet may improve intestinal epithelial morphology and integrity, and these improvements are more evident when piglets are fed diets with 24.0% CP.

Effect of repeated administration of lipopolysaccharide on inflammatory and stress markers in saliva of growing pigs.

Although saliva could be considered to be an ideal biological sample for evaluation of biomarkers relating to stress and inflammatory responses in pigs, little is known about how these might be influenced by the presence of endotoxaemia. In the present study, the response to repeated administrations of lipopolysaccharide (LPS) was investigated, using a panel of salivary stress markers such as chromogranin A (CgA) and cortisol, as well as inflammatory/immune markers such as haptoglobin (Hp), C-reactive protein (CRP) and immunoglobulin A (IgA). Sixteen growing pigs were adapted to experimental conditions for 3 weeks, after which, 10 of the pigs were selected to receive three doses of LPS at 48 h intervals. Saliva samples were taken from all pigs prior to any LPS administration (baseline) and at time points corresponding to 3 h after each injection of LPS (T1, T2 and T3). Results showed that repeated administration of LPS induced significant elevation of salivary markers of hypothalamic-pituitary-adrenal (cortisol) and immune (Hp, CRP and IgA) activity compared to baseline levels (P < 0.05). However, rectal temperature, CRP and cortisol data suggested that the amplitude of the inflammatory response decreased with successive LPS administrations. Thus, measurement of salivary biomarkers could be a practical tool for evaluating the inflammatory response to endotoxaemia in pigs. In the case of chronic inflammatory states, salivary Hp and IgA might be more sensitive markers than CRP or cortisol.

High ambient temperature alleviates the inflammatory response and growth depression in pigs challenged with Escherichia coli lipopolysaccharide.

Pig production has increased in hot climate countries over recent years, but the effect of exposure to high temperatures on the health status of farm animals has not been investigated thoroughly. It is not clear how the ambient temperature (Ta) might influence responses to inflammatory challenge in pigs. The aim of the present study was to evaluate the effects of high Ta on performance and physiological parameters of growing pigs, subjected to repeated administration of Escherichia coli lipopolysaccharide (LPS). Thirty-seven pigs, each fitted with a jugular catheter, were assigned to one of two Ta conditions: thermo-neutral (TN, 24 °C) or high (HT, 30 °C). After a 14-day adaptation period, and a 7-day measurement period, pigs were administered five repeated injections of LPS at 48 h intervals. Irrespective of Ta, the LPS challenge reduced feed consumption and increased plasma pro-inflammatory cytokines, haptoglobin and cortisol. However, the extent of these responses was greater in pigs at TN than HT. In both groups, plasma thyroxine and triiodothyronine concentrations decreased, following the first LPS injection and thereafter returned to baseline, which occurred faster at HT than at TN. Moreover, the LPS challenge decreased growth and feed efficiency in pigs kept at TN, which was not observed in pigs kept at HT. The results suggest a greater capacity of pigs to limit the physiological and metabolic disturbances caused by inflammatory challenge, when kept at HT, compared to TN.