Blood metabolite changes and live weight loss following brown seaweed extract supplementation in goats subjected to stress

Abstract

Brown seaweed ( Ascophyllum nodosum) extract supplementation has been reported to have several beneficial effects in farm animals, but its effects during stressful situations have not been adequately studied. Female Spanish (S) (mean body weight 40.1 ± 5.9 kg) and Boer × Spanish (BS) (mean weight 38.5 ± 4.5 kg) goats (8 to 10 months; n = 20/breed) were housed in pens (5 does/pen) and fed an alfalfa pelleted diet plus a pellet supplement (marketed as Tasco) - with or without seaweed extract (treatment) for 3 weeks. The supplement was given at 40% of daily intake to allow for 2% of seaweed extract in the diet. The animals were weighed immediately before and after a 6 h-transportation period, as well as after overnight holding, to assess live weight loss as a percentage of the initial body weight. Blood samples were collected following 0, 2, and 6 h of transportation, and after holding (24 h) to assess the stress responses. The goats were kept on their respective diets for one week following the transportation trial, and rumen fluid samples collected to analyze VFA's, pH and ammonia content. Live weight loss was greater in BS does than in the S does due to transportation ( P < 0.05) and transportation plus holding ( P < 0.01). Treatment did not influence the plasma urea nitrogen (PUN), non-esterified fatty acid (NEFA) concentrations and creatine kinase (CK) activity. At the end of the dietary treatment (0 h), the PUN concentrations were 23.1 and 22.9 mg/dl (S.E.M. = 0.7); and the NEFA concentrations were 190.8 and 170.1 mEq/l (S.E.M. = 12.5) in the control and treated group, respectively. Plasma glucose concentrations were 100.9 and 101.6 mg/dl (S.E.M. = 6.6) in the control and treated group, respectively, and were influenced by treatment × breed × time ( P < 0.01). Plasma CK activity also increased due to transportation and peaked at 6 h, but decreased after holding ( P < 0.01). The CK activities were 130.2, 173.6, 197.8, and 180.4 IU (S.E.M. = 17.7) at 0, 2, 6, and 24 h, respectively, while the rumen VFA's were not affected by the dietary treatment and the pH was lower ( P < 0.05) in the seaweed-supplemented goats compared to the control goats. Rumen fluid pH was lower ( P < 0.05; 6.6 versus 6.9) and ammonia higher ( P < 0.01; 109.9 versus 103.1) in the Spanish does, compared to the crossbreds. Live weight loss and stress responses significantly differed in the different breeds of goats. This study showed that seaweed extract supplementation does not affect live weight loss or blood metabolite levels during transportation stress in goats.