Effect of supplementing varying inclusion levels of laminarin and fucoidan on growth performance, digestibility of diet components, selected faecal microbial populations and volatile fatty acid concentrations in weaned pigs

A 3 × 2 factorial experiment was conducted to investigate the effect of dietary supplementation of purified laminarin (LAM) and fucoidan (FUC), independently or in combination on growth performance, coefficient of total tract apparent digestibility (CTTAD), selected faecal microbial populations and volatile fatty acid concentrations (VFA) in weaned pigs. At weaning, 168 pigs (24 days of age, 6.8 ± 0.6 kg live weight) were assigned to one of six dietary treatments (n = 14): (1) basal diet; (2) basal diet + 240 mg/kg FUC; (3) basal diet + 150 mg/kg LAM; (4) basal diet + 150 mg/kg LAM and 240 mg/kg FUC; (5) basal + 300 mg/kg LAM; (6) basal diet + 300 mg/kg LAM and 240 mg/kg FUC. The pigs were offered the diets ad libitum for 35 days post-weaning. Pigs offered 300 mg/kg LAM supplemented diets had a higher average daily gain (ADG) throughout the entire experimental period (d 0–35) compared with pigs offered diets with 0 mg/kg and 150 mg/kg LAM supplementation (0.374 kg/d vs. 0.346 kg/d vs. 0.340 kg/d, SEM ± 0.0094; P < 0.05). There was an interaction between LAM and FUC supplementation on gain to feed (G:F) ratio (P < 0.05) during the entire experimental period. Pigs offered the 300 mg/kg LAM diet had a higher G:F ratio than pigs offered the basal diet. However, there was no effect of the 300 mg/kg LAM on overall G:F ratio when combined with FUC. There was an interaction between LAM and FUC supplementation on the CTTAD of gross energy (GE) (P < 0.05). Pigs offered the 150 mg/kg or 300 mg/kg LAM diets had an increased CTTAD of GE compared with pigs offered the basal diet. However, there was no further effect of LAM on the CTTAD of GE when combined with FUC. Pigs offered diets supplemented with FUC had an increased faecal Lactobacillus population compared with pigs offered diets without FUC supplementation (10.11 gene copy number/g vs. 9.62 gene copy number/g, SEM ± 0.173; P < 0.05). Pigs offered the 150 mg/kg and 300 mg/kg LAM supplemented diets had an improved faecal consistency from d 7–14 compared with pigs offered diets without LAM supplementation (3.14 vs. 3.00 vs. 3.49, SEM ± 0.348; P < 0.05). In summary, the inclusion of 300 mg/kg LAM showed the greatest benefit in growth performance with improvements in ADG and G:F ratio partially due to an increased CTTAD of diet components and lower faecal score.