Physical processing of barley and its effects on intra-caecal fermentation parameters in ponies

Intra-caecal fermentation parameters in caecally-fistulated ponies offered barley based diets in which the barley had been physically processed by either rolling (RB), micronising (MB) or extruding (EB). Three ponies were offered 4 kg dry matter (DM) per day of either 100% hay cubes (HC), or one of three diets consisting of a 50:50 barley:HC mix. Due to small refusals of HC, the actual DM intakes (kg per day) were 3.74, 3.67, 3.57 and 3.52 (S.E.D. 0.18) for the HC, RB:HC, MB:HC and EB:HC diets, respectively. With the exception of butyrate, all intra-caecal fermentation parameters 4-8 h post feeding in ponies given diet RB:HC were significantly (P<0.05) different from those observed in ponies fed diet HC. Thus, in ponies fed diet RB:HC, intra-caecal pH and acetate molar proportions were reduced whilst lactate concentration and propionate molar proportions were increased (P<0.05) compared with values recorded in ponies fed diet HC. By contrast, intra-caecal total VFA, lactate and pH levels of ponies fed diets MB:HC or EB:HC were similar to those in ponies fed HC at all time points measured, although acetate and propionate molar proportions were lower and higher, respectively, in ponies fed diets EB:HC and MB:HC compared with those fed HC. These results suggest that micronisation or extrusion of barley offer advantages over rolling barley in that the values for the intra-caecal fermentation parameters in ponies fed MB:HC or EB:HC were largely similar to those of ponies fed the HC forage diet. Where equines are to be given substantial quantities of cereals in their diet then use of micronised or extruded products may be beneficial in minimising hindgut dysfunction. (C) 2000 Elsevier Science B.V

Physical processing of barley and its effects on intra-caecal fermentation parameters in ponies

Intra-caecal fermentation parameters in caecally-fistulated ponies offered barley based diets in which the barley had been physically processed by either rolling (RB), micronising (MB) or extruding (EB). Three ponies were offered 4 kg dry matter (DM) per day of either 100% hay cubes (HC), or one of three diets consisting of a 50:50 barley:HC mix. Due to small refusals of HC, the actual DM intakes (kg per day) were 3.74, 3.67, 3.57 and 3.52 (S.E.D. 0.18) for the HC, RB:HC, MB:HC and EB:HC diets, respectively. With the exception of butyrate, all intra-caecal fermentation parameters 4-8 h post feeding in ponies given diet RB:HC were significantly (P<0.05) different from those observed in ponies fed diet HC. Thus, in ponies fed diet RB:HC, intra-caecal pH and acetate molar proportions were reduced whilst lactate concentration and propionate molar proportions were increased (P<0.05) compared with values recorded in ponies fed diet HC. By contrast, intra-caecal total VFA, lactate and pH levels of ponies fed diets MB:HC or EB:HC were similar to those in ponies fed HC at all time points measured, although acetate and propionate molar proportions were lower and higher, respectively, in ponies fed diets EB:HC and MB:HC compared with those fed HC. These results suggest that micronisation or extrusion of barley offer advantages over rolling barley in that the values for the intra-caecal fermentation parameters in ponies fed MB:HC or EB:HC were largely similar to those of ponies fed the HC forage diet. Where equines are to be given substantial quantities of cereals in their diet then use of micronised or extruded products may be beneficial in minimising hindgut dysfunction. (C) 2000 Elsevier Science B.V

Postprandial insulin responses to various feedstuffs differ in insulin dysregulated horses compared with non‐insulin dysregulated controls

BACKGROUND: Controlling postprandial hyperinsulinaemia is important in insulin dysregulated (ID) horses to reduce the risk of laminitis. OBJECTIVES: To evaluate postprandial insulin responses of ID versus non-insulin dysregulated (NID) horses to feedstuffs varying in nonstructural carbohydrate (NSC) and crude protein (CP). STUDY DESIGN: Randomised crossover. METHODS: Eighteen adult mixed-breed horses (13.3 ± 2.2 years; 621 ± 78.8 kg) were individually fed [~1 g/kg body weight (BW)] specific feedstuffs within two crossover studies. Eight ID and eight NID were used in Study A, and 11 ID and 5 NID in Study B. In Study A, all horses were randomly fed once: cracked corn (CC: ~74% NSC & ~9% CP), ration balancer with low protein (RB-LP: ~15% NSC & ~17% CP), ration balancer with high protein (RB-HP: ~14% NSC and ~37% CP) and 50:50 mixture of RB-LP:RB-HP (MIX-P). In Study B, horses were randomly fed once: CC, RB-HP, steam-flaked corn (SF: ~73% NSC & ~10% CP), oat groats (OG: ~64% NSC & ~14% CP) and a low NSC pellet (L-NSC: ~6% NSC & ~12% CP). Blood was collected for insulin determination [radioimmunoassay (RIA)] before and 30, 60, 75, 90, 105, 120, 150, 180, 210 and 240-minute post-feeding in Study A and at 60-minute in Study B. Data were analysed via analysis of variance (ANOVA) for repeated measures after any required transformations. RESULTS: ID horses had significantly greater insulin responses (AUCi) than NID for all diets in both studies (P < .001; ID 22 362 ± 10 298 µIU/mL/min & NID 6145 ± 1922 µIU/mL/min). No effect of diet on AUCi for NID (P = .2), but in ID, the CC (32 000 ± 13 960 µIU/mL/min) AUCi was higher than RB-LP (P = .01; 18 977 ± 6731 µIU/mL/min). ID insulin (T60) was lower for the L-NSC (57.8 ± 18.5 µIU/mL) versus all other diets (P < .02; 160.1 ± 91.5 µIU/mL). MAIN LIMITATIONS: Small numbers of horses; no ponies. CONCLUSIONS: NSC appears to be the main driver of the postprandial insulin response. ID horses respond disproportionately to feeding even small amounts of low/moderate NSC feedstuffs. Data on possible dietary thresholds for postprandial insulin responses cannot be extrapolated from NID horses