15Polysaccharides obtained from macroalgae have promising prospects both at research and 16 industrial level, and could contribute greatly to the future of marine based bio-economy.

This study examined the relationship between feed efficiency and performance, and feeding behavior, blood metabolic variables, and various ultrasonic measurements in finishing beef heifers. Within-animal repeatability estimates of feed intake and behavior, performance, feed efficiency, ultrasonic body measures, and plasma analytes across the growing and finishing stages of the lifespan of the animal were also calculated. Fifty heifers previously ranked as yearlings on phenotypic residual feed intake (RFI) were used. Animals [initial BW = 418 (SD = 31.5) kg] were offered a TMR diet consisting of 70:30 concentrate and corn silage on a DM basis (ME 10.7 MJ/kg of DM; DM 530 g/kg) for 84 d. Feeding duration (min/d) and feeding frequency (events/d) were calculated for each animal on a daily basis using a computerized feeding system. Ultrasonic kidney fat and lumbar and rump fat and muscle depths were recorded on 3 equally spaced occasions during the experimental period. Blood samples were collected by jugular venipuncture on 4 occasions during the experimental period and analyzed for plasma concentrations of IGF-I, insulin, and various metabolites. Phenotypic RFI was calculated for all animals as the residuals from a regression model regressing DMI on ADG and midtest BW(0.75). Repeatability was calculated for several traits both within and between production phase using intraclass correlation and Pearson correlation coefficients as appropriate. Overall ADG, DMI, G:F, and RFI were 1.17 kg/d (SD = 0.19), 10.81 kg/d (SD = 1.02), 0.11 kg of BW gain/kg of DM (SD = 0.02), and 0.00 kg of DM/d (SD 0.59). Daily feeding events and eating rate tended to be positively correlated (P = 0.08) with RFI. Ultrasonic kidney fat depth tended to be related to G:F (r = -0.28; P = 0.07), and kidney fat accretion tended to be related to RFI (r = 0.29; P = 0.08). Plasma urea (r = 0.38; P < 0.01), β-hydroxybutyrate (r = 0.40; P < 0.01), and insulin (r = 0.23; P = 0.07) concentrations were correlated with RFI. Plasma glucose (r = -0.25; P = 0.07), glucose:insulin (r = 0.33; P < 0.05), and insulin (r = -0.30; P < 0.05) were associated with G:F. However, systemic IGF-I was unrelated (P > 0.10) to any measure of feed efficiency. Repeatability estimates within the finishing period for DMI, feeding duration, feeding events, feed intake/feeding event, and eating rate were 0.34, 0.37, 0.60, 0.62, and 0.56, respectively. Repeatability estimates (P < 0.001) between the growing and finishing phases for DMI, G:F, and RFI were r = 0.61, r = 0.37, and r = 0.62, respectively. Moderate to strong repeatability values (ranging from r = 0.40 to 0.76; P < 0.001) were obtained for feeding behavior traits between the yearling and finishing phases. We conclude that RFI and feeding behavior are repeatable traits and that some plasma analytes may be potential indicators of RFI in beef cattle.

An experiment (complete randomised design) was conducted to investigate the effects of Laminaria hyperborea and Laminaria digitata seaweed extract inclusion on gut morphology, selected intestinal microbiota populations, volatile fatty acid concentrations and the immune status of the weaned pig. Twenty-eight piglets (24 days of age, 6.5 6 1.4 kg live weight) were assigned to one of four dietary treatments for 7 days and then sacrificed: (T1) basal diet (control); (T2) basal diet and 1.5 g/kg L. hyperborea seaweed extract; (T3) basal diet and 1.5 g/kg L. digitata seaweed extract; and (T4) basal diet and 1.5 g/kg of a combination of L. hyperborea and L. digitata seaweed extract. The seaweed extract contained both laminarin and fucoidan. Digesta samples were taken from the caecum and colon to measure the enterobacteria, bifidobacteria and lactobacilli populations and for volatile fatty acid analysis. Tissue samples were taken from the duodenum, jejunum and ileum for morphological examination. Blood samples were taken to determine the cytokine gene expression profile and to measure the phagocytotic capacity of the blood. Pigs offered diets containing L. hyperborea seaweed extract had less bifidobacteria in the colon (P , 0.05) and lactobacilli in the caecum (P , 0.05) and colon (P , 0.001). The inclusion of L. digitata seaweed extract resulted in lower populations of enterobacteria in the caecum and colon (P , 0.01), bifidobacteria in the caecum (P , 0.05), and lactobacilli in the caecum (P , 0.05) and colon (P , 0.001). Pigs offered the combination of L. hyperborea and L. digitata seaweed extracts had less enterobacteria (P , 0.05) and lactobacilli (P , 0.01) in the caecum and colon. Pigs offered the L. digitata-supplemented diet had a reduced villous height in the duodenum and jejunum (P , 0.05). The inclusion of the L. digitata seaweed extract increased the molar proportion of butyric acid in the colon (P , 0.05). There was a significant reduction in the ammonia concentration in the colon with the inclusion of L. hyperborea (P , 0.01) and L. digitata (P , 0.05) seaweed extracts. An increase in the expression of the Interleukin-8 mRNA was observed on day 6 with the supplementation of the combination of L. hyperborea and L. digitata seaweed extract (P , 0.05). The inclusion of L. hyperborea seaweed extract resulted in an increase in total monocyte number (P , 0.05). In conclusion, the supplementation of L. hyperborea and L. digitata seaweed extract alone and in combination reduced the enterobacteria, bifidobacteria and lactobacilli populations in the caecum and colon, while only marginal effects on the immune response was observed.

A 2 £ 2 factorial experiment was conducted to investigate the interactions between laminarin (LAM; 0 and 300 parts per million (ppm)) and fucoidan (FUC; 0 and 240 ppm) levels on intestinal morphology, selected microbiota and inflammatory cytokine gene expression in the weaned pig. There was an interaction between LAM and FUC supplementation on the Enterobacteriaceae population (P,0·05) and the abundance of attaching and effacing Escherichia coli (AEEC) strains (P, 0·05) in the colon. Pigs offered the FUC diet had a reduced Enterobacteriaceae population compared with pigs offered the basal diet. However, the effect of FUC on the Enterobacteriaceae population was not observed when combined with LAM. Pigs offered the LAM diet had reduced abundance of AEEC strains compared with pigs offered the basal diet. However, there was no effect of LAM on the abundance of AEEC strains when combined with FUC. There was an interaction between LAM and FUC supplementation on villous height (P,0·01) and the villous height:crypt depth ratio (P,0·01) in the duodenum. Pigs offered the LAM or FUC diet had an increased villous height and villous height:crypt depth ratio compared with pigs offered the basal diet. However, there was no effect of the LAM and FUC combination diet on intestinal morphology. Pigs offered the LAM-supplemented diets had a lower IL-6 (P, 0·05), IL-17A (P, 0·01) and IL-1b (P,0·01) mRNA expression in the colon compared with pigs offered the diets without LAM. In conclusion, supplementation with either LAM or FUC alone modified intestinal morphology and selected intestinal microbiota, but these effects were lost when offered in combination.

No abstract

BACKGROUND: In experiment 1, 30 boars were assigned to one of five treatments (n = 6): T1, 0 g kg −1 seaweed extract (SWE); T2, 0.7 g kg −1 SWE; T3, 1.4 g kg −1 SWE; T4, 2.8 g kg −1 SWE and T5, 5.6 g kg −1 SWE. The extract contained laminarin and fucoidan only and was extracted from Laminaria spp. In experiment 2, 28 boars were assigned, in a 2 × 2 factorial to one of four treatments (n = 7): T1, control; T2, control plus 300 mg laminarin; T3, control plus 240 mg fucoidan; T4, control plus 300 mg laminarin and 240 mg fucoidan kg −1 diet.

b-Glucans have been identified as natural biomolecules with immunomodulatory activity. The first objective of the present study was to compare the effects of purified b-glucans derived from Laminaria digitata, L. hyperborea and Saccharomyces cerevisiae on piglet performance, selected bacterial populations and intestinal volatile fatty acid (VFA) production. The second aim was to compare the gene expression profiles of the markers of pro-and anti-inflammation in both unchallenged and lipopolysaccharide (LPS)-challenged ileal and colonic tissues. b-Glucans were included at 250 mg/kg in the diets. The b-glucans derived from L. hyperborea, L. digitata and S. cerevisiae all reduced the Enterobacteriaceae population (P, 0·05) without influencing the lactobacilli and bifidobacteria populations (P.0·05) in the ileum and colon. There was a significant interaction between gastrointestinal region and b-glucan source in the expression of cytokine markers, IL-1a (P,0·001), IL-10 (P,0·05), TNF-a (P, 0·05) and IL-17A (P,0·001). b-Glucans did not stimulate any pro-or anti-inflammatory cytokine markers in the ileal epithelial cells. In contrast, the expression of a panel of pro-and anti-inflammatory cytokines (IL-1a, IL-10, TNF-a and IL-17A) was down-regulated in the colon following exposure to b-glucans from all the three sources. However, the data suggest that the soluble b-glucans derived from L. digitata may be acting via a different mechanism from the insoluble b-glucans derived from L. hyperborea and S. cerevisiae, as the VFA profile was different in the L. digitata-treated animals. There was an increase in IL-8 gene expression (P, 0·05) in the gastrointestinal tract from the animals exposed to L. digitata following an LPS ex vivo challenge that was not evident in the other two treatment groups. In conclusion, b-glucans from both seaweed and yeast sources reduce Enterobacteriaceae counts and pro-inflammatory markers in the colon, though the mechanisms of action may be different between the soluble and insoluble fibre sources.

A 2 × 2 factorial experiment was conducted to investigate the interaction between cereal type (wheatv. barley) and an exogenous enzyme supplement (with or without) on nutrient digestibility, large intestinal microflora, volatile fatty acid profile andin vitromanure ammonia emissions from finisher pigs. The enzyme supplement used contained endo-1, 3-β-glucanase (EC 3·2·1·6) and endo-1, 4-β-xylanase (EC 3·2·1·8). The diets were formulated to contain similar concentrations of net energy (9·8 MJ/kg) and lysine (10·0 g/kg). Urine and faeces were collected over seven consecutive days from 16 boars (four boars per treatment, 80·0 kg live weight) that were housed in metabolism crates. After collections, the pigs were slaughtered and the contents of the intestinal tracts were removed for analysis. There was a significant interaction between cereal type and enzyme inclusion in the apparent total tract digestibility of dry matter (DMD), organic matter (OMD) and nitrogen. The inclusion of an enzyme supplement in barley-based diets increased (P< 0·05) DMD, OMD and nitrogen digestibility compared with unsupplemented diets, however there was no effect of enzyme supplementation in wheat-based diets. There was a significant interaction between cereal type and enzyme inclusion in selected components of the gut microflora. Pigs offered unsupplemented barley-based diets had higher populations of bifidobacteria (P< 0·05) in the caecum and colon than those on the enzyme supplemented barley diet, however, there was no effect of enzyme supplementation on bifidobacteria in wheat-based diets. There was a significant interaction between cereal type and enzyme inclusion in volatile fatty acid production and inin vitroammonia emissions. In the absence of an enzyme supplement, barley-based diets reduced the proportion of isovaleric acid (P< 0·05) and isobutyric acid (P< 0·05) in the caecum and colon and also reduced manure ammonia emissions during storage from 0 to 240 h (P< 0·05) compared with the wheat-based diet, however there was no effect of cereal type in enzyme-supplemented diets. In conclusion, the inclusion of an enzyme in barley-based diets increased nutrient digestibility but also increased ammonia emissions.