Creatine, (CREA) a central constituent in energy metabolism, is obtained from dietary animal protein or de novo synthesis from guanidinoacetic acid (GAA). Especially in all-vegetable diets, supplemental CREA or GAA may restore the CREA availability in tissues, and hence, improve performance. In this study, 768 one-d-old male Ross 308 broilers were assigned to 1 of 4 diets: negative control, all-vegetable corn-soybean-based; negative control supplemented with either 0.6 or 1.2 g of GAA per kilogram of feed; and positive control (60, 30, and 30 g/kg of fish meal in the starter, grower, and finisher diets, respectively). Each treatment was replicated in 6 pens of 32 birds each. At the end of the grower period (d 26), 2 birds per pen were euthanized for metabolic measurements. Four broilers per pen were selected at slaughter age (d 39) to determine carcass characteristics and meat quality. Compared with the negative control, GAA supplementation resulted in an improved gain:feed ratio (P < 0.05) and ADG (P < 0.05; + 2.7 and + 2.2% for GAA at 0.6 and 1.2 g/kg, respectively) throughout the entire period. Breast meat yield was higher for the GAA diets compared with that of the negative control birds (P < 0.05; 30.6 vs. 29.4%) and was comparable with that of the positive control birds (30.2%). With regard to meat quality, lower ultimate pH values, higher cooking and press fluid losses, and higher color L* values were observed for the GAA diets compared with those of the negative control diet (P < 0.05). These effects were small, however. The GAA and CREA levels in breast meat were lower and higher, respectively, in GAA-fed birds compared with those of the control birds (P < 0.01). The diets did not affect plasma metabolic traits, except that plasma insulin-like growth factor I concentrations were almost twice as high in animals fed 1.2 g/kg of GAA compared with those of all other treatments. The GAA included in all-vegetable diets improved animal performance for the whole rearing period and increased breast meat yield.

BACKGROUND: The essential oils (EO) carvacrol, thymol, eugenol and trans-cinnamaldehyde have welldocumented antimicrobial properties and offer therefore an alternative for the antimicrobial growth promoters in pig feeds. The aim of this work was to determine the degradation and kinetics of these EO along the gastrointestinal tract (GIT) of piglets, which is necessary information for correct application in pig feeds.

Two trials were conducted to study the effects of dose and formulation of carvacrol and thymol on bacterial counts, metabolites and functional traits of the gut in weaned piglets. In the first experiment (Exp. I), 25 piglets (28 d, 6.59 +/- 0.48 kg BW) were allocated to five dietary treatments: a control diet, or the same diet supplemented with either carvacrol or thymol at doses of 500 and 2000 mg kg(-1). In the second experiment (Exp. II), 35 piglets (28 d, 7.99 +/- 0.73 kg BW) were assigned to seven dietary treatments: the same control diet as in Exp. I, or this diet supplemented with thymol in one of three formulations (on celite, on alphacel or microencapsulated) at doses of 500 and 2000 mg kg(-1). At 11/12 days post-weaning piglets were euthanised, and digesta from stomach, proximal and distal small intestine were sampled for bacteriological and biochemical analysis. Small intestinal tissue was sampled for histomorphological determinations. In none of the experiments or sections of the gut was the number of bacteria lowered by the carvacrol or thymol supplementation. In Exp. I, the villus/crypt ratio at the distal small intestine for the experimental diets (1.30-1.32) was higher than for the control diet (1.24) (p < 0.05). Thymol fed animals in Exp. II had a lower number of intra-epithelial lymphocytes at the proximal (p < 0.05) and at the distal (p < 0.1) small intestine as compared to control animals. Mean concentration of the active ingredient in the stomach and proximal small intestine for the 2000 mg kg(-1) carvacrol diet was 521 and 5 mg kg(-1) fresh digesta, respectively, and for the 2000 mg kg(-1) thymol diets it ranged between 475 and 647 and between 13 and 24 mg kg(-1) fresh digesta, respectively. Cumulative absorption in the proximal small intestine was higher than 90% for all treatments and was not affected by formulation type. These data suggest that carvacrol and thymol can improve gut health, but evidence for clear antimicrobial effects towards the major culturable bacteria of the pig foregut is limited.

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BACKGROUND: Limited research suggests that brown seaweed (extracts) may be used in pig nutrition for improving gut health and performances and for iodine enrichment of tissues. One in vitro and two in vivo experiments with dried iodine-rich intact marine seaweed (Ascophyllum nodosum) have been conducted with weaned piglets to further unravel the mechanisms. RESULTS: In vitro investigations revealed a statistically significant depressive effect of seaweed on pig gut flora, especially on Escherichia coli. In vivo, seaweed (10 g kg −1 ) had a reducing effect on the E. coli load in the stomach (P = 0.07) and small intestine (P < 0.05), while the lactobacilli/E. coli ratio was enhanced (P < 0.05) in the small intestine, indicating a beneficial shift in the microbial population. Statistically significant increases (P < 0.001) in iodine content were noted for several tissues in piglets on seaweed (20 g kg −1 , corresponding to 10 mg iodine kg −1 feed) compared with the control diet (1 mg iodine kg −1 feed).