Performance of weanling piglets offered low-, medium- or high-lactose diets supplemented with a seaweed extract from Laminaria spp.

An experiment (3 × 4 factorial arrangement) was conducted to investigate the interaction between different levels of lactose (60 v. 150 v. 250 g/kg) and seaweed extract (0 v. 1 v. 2 v. 4 g/kg) containing both laminarin and fucoidan derived from Laminaria spp. on growth performance and nutrient digestibility of weanling pigs. In all, 384 piglets (24 days of age, 7.5 kg (s.d. 1 kg) live weight) were blocked on the basis of live weight and were assigned to one of 12 dietary treatments (eight replicates per treatment). Piglets were offered diets containing either low (60 g/kg), medium (150 g/kg) or high (250 g/kg) lactose levels with one of the following levels of seaweed extract additive: (1) 0 g/kg, (2) 1 g/kg, (3) 2 g/kg or (4) 4 g/kg seaweed extract. The pigs were offered the diets ad libitum for 21 days post weaning. There was a significant lactose × seaweed extract interaction (P < 0.05) in average daily gain (ADG) during the experimental period (days 0 to 21). At the low and medium levels of lactose, there was an increase in ADG as the level of seaweed extract increased to 2 g/kg (P < 0.05). However, at the high level of lactose there was no further response in ADG as the level of seaweed extract increased above 1 g/kg. There was a significant lactose × seaweed extract interaction during the experimental period (days 0 to 21) (P < 0.05) on the food conversion ratio (FCR). At the low level of lactose, there was a significant improvement in FCR as the levels of seaweed extract increased to 4 g/kg (P < 0.01). At the medium level of lactose, there was a significant improvement in FCR as seaweed extract increased to 2 g/kg. However, there was no significant effect of seaweed extract on FCR at the high levels of lactose (P > 0.05). There was a linear increase in average daily feed intake (ADFI) during the experimental period (days 0 to 21) (P < 0.05) as levels of seaweed extract increased. There was a linear increase in ash digestibility (P < 0.01) during the experimental period (days 0 to 21) as the level of lactose increased. There was a quadratic decrease (P < 0.01) in nitrogen (N) and neutral detergent fibre digestibility as the levels of lactose increased. In conclusion, pigs responded differently to the inclusion levels of seaweed extract at each level of lactose supplementation. The inclusion of a laminarin-fucoidan extract in piglet diets may alleviate the use for high-lactose diets (>60 g/kg) and would also alleviate some of the common problems that occur post weaning.

The effects of seaweed extract inclusion on gut morphology, selected intestinal microbiota, nutrient digestibility, volatile fatty acid concentrations and the immune status of the weaned pig.

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 ± 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.

Effort, interest, and recall: beliefs and behaviors of preschoolers.

Sixty preschoolers participated in two experimental sessions designed to measure their beliefs about the relations between effort, interest, and recall as well as their actual effort deployment and recall under different interest levels. In Session 1, children made paired-comparison judgments about the individual and combined effects of high versus low effort and high versus low interest on recall. In Session 2, the children's effort deployment (behavior during study), recall, and attributions for recall in high versus low interest conditions were examined. Findings from Session 1 indicated that the children believed that recall increases with effort and with interest. They also believed that interest influences the amount of effort expended during study such that high interest elicits high effort and leads to superior recall relative to a low interest-low effort combination. Findings from Session 2 indicated that these beliefs were quite naive; that is, interest level did influence the children's effort deployment during study but the effects were more complex than the children had predicted. Contrary to the children's beliefs, effort was not related to recall and recall was superior in the low- not the high-interest condition. Consistent sex differences in beliefs, behavior, and recall performance were found. Compared with boys, most girls held naive beliefs about effort and interest and this naivete was associated with strategic behavior and recall performance advantages. The findings are discussed in terms of the importance and limitations of preschoolers' beliefs about memory.

Children's metamemory about the influence of conceptual relations on recall.

Developmental differences in children's metamemory about the influence of conceptual relations on free recall were examined. First, third, and fifth grade children memorized two lists of words, a two-category (items blocked by category) and an unrelated list. On both lists, four metamemory measures were obtained from each subject. These were estimates of recall performance, estimates of the cognitive effort associated with that recall performance, causal attributions about recall, and reports of strategy use. At each grade, subjects recalled more words on the related than the unrelated list and demonstrated reliable clustering at recall for the related words. Metamemory about the influence of conceptual relations was demonstrated at each grade level, but the nature of that metamemory changed with age. Even the youngest children realized that their recall performance would be superior on the related list but they did not understand how or why their recall was facilitated. With age, children attributed superior recall of the related material to the categorical relations in the stimuli, reported using categorical organization strategies, and demonstrated increasing awareness of the facilitative effects of conceptual relations on cognitive effort. Older children used their metamemory to direct their use of organizational strategies and to enhance recall on the related list. However, the four aspects of metamemory were not well coordinated at any grade level. The findings are discussed in terms of the importance of developing comprehensive, well-elaborated models of metamemory development.

Metamemory and memory construction.

In this article, we present the contemporary conceptualization of metamemory as beliefs, accurate and naive, about memory. We discuss the implications of metamemory for memory construction in general and for suggestibility and the recovery of memories in particular. We argue that beliefs about memory influence (a) the probability that suggestions will be incorporated into memory and (b) judgments about the veracity of subsequent recollections. Implications for research on the role of beliefs in suggestibility and memory recovery are outlined.