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Glucose and insulin concentrations in restricted pasture-fed horses
Abstracts / Journal of Equine Veterinary Science 33 (2013) 321-399
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markers (PGE2, TNF-a, IFN-g). However, plasma eicosapentaenoic acid concentrations were higher in horses on the SOY diet (0.45 0.07 percent of total plasma lipid) than horses on FLAX and ALG (P< 0.05), and plasma a-linolenic acid was altered in response to treatment (P< 0.05) with horses on FLAX having the greatest percentage. Serum interleukin-10 concentrations were lower in SOY than in ALG (P< 0.05). The results of this study indicate that mature exercising horses free from osteoarthritis do not exhibit physiological anti-inflammatory benefits when supplemented with a low dose of omega-3 fatty acids over a 21-d period. This study suggests a higher dose of DHA may need to be offered. Alternatively, if feeding DHA at an amount lower than 30 to 35 g/d, supplementation longer than 21-d may be required to observe potential differences in plasma FA concentrations. To our knowledge, this is the first study to supplement n-3 FA in the form of DHA-rich microalgae (DRM) to exercising horses. As nothing is known about potential differences in bioavailability of a DRM source of DHA in the horse, additional research is needed with an amount greater than 28.4 g/d for a 21-d period of DHA to validate the effects of a DRM DHA source on metabolic effects of DHA in the horse.
sequence of treatment as the main effects, and horse within sequence as the subject. In Exp. 1, mean pasture NSC concentrations at the start of grazing for DAY was 14.3 0.8% and increased (P<0.01) to a peak value of 18.3 0.8% 10 hr later, and then decreased (P<0.001) to 11.8 1.1% by 0700 the next morning. In Exp. 2, mean NSC concentrations was 16.8 1.7% at the start of grazing for DAY and remained unchanged until 0300 the next morning, when it decreased (P <0.05) to 10.9 1.7% and remained unchanged for the duration of the NIGHT grazing. In both experiments, logPI was higher (P<0.05) in NIGHT than DAY, and in Exp 2. NIGHT was also higher (P<0.05) than CTRL. In Exp. 1, mean logAUCI was greater (P<0.01) for CTRL than DAYand NIGHT. In Exp. 2, logAUCI for DAY was less (P<0.05) than CRTL and NIGHT. Glucose concentrations were not affected by treatment. These data suggest that while continuous grazing results in elevated insulin concentrations throughout the day, the highest insulin concentrations are achieved in horses turned out in the evening. Horses with metabolic conditions should avoid turnout at these times.
Glucose and insulin concentrations in restricted pasture-fed horses
E.D. Lamprecht 1, B.D. Nielsen 2, and C.I. Robison 2 1 Cargill, Incorporated, Elk River, MN 55330, 2 Department of Animal Science, Michigan State University, East Lansing, MI, USA 48824-1225
S.E. Pratt-Phillips, C. Wycoff, C. Sykes, J. Kutzner-Mulligan, and P.D. Siciliano Department of Animal Science, North Carolina State University, Raleigh, NC 27695 Two experiments were conducted to determine the effect of 10-h restricted grazing during the day-light (DAY) and night-time (NIGHT), compared to continuous grazing (CTRL), on changes in blood glucose and insulin concentrations. Experiments 1 and 2 were conducted during the spring and subsequent fall, respectively. For both experiments, a completely randomized crossover design was used. Twelve mature stock-type geldings (583 48 kg) were randomly assigned to one of three treatments (DAY, NIGHT or CTRL) for a period of 10 d. Following each 10-d period, horses were assigned to a new treatment so that all horses were exposed to all treatments. For the DAY group, grazing began at 1000 h and ended at 1800 h (except for Period 1 of Exp. 1 where grazing was from 1100 h – 2100 h). For the NIGHT group, grazing began at 2100 h and ended at 0700 h. Pasture consisted of predominantly tall fescue. On day 9, horses were fitted with jugular catheters and blood samples were collected hourly for a 24-h period. If a horse was at pasture, pasture samples were also collected every other hour and analyzed for NSC by wet chemistry. Plasma glucose and serum insulin concentrations were determined by spectroscopy and RIA, respectively. Area under the curve for glucose (AUCG) and insulin (AUCI), and peak glucose (PG) and insulin (PI) were determined, and insulin values were logged to obtain a normal distribution of the data. Glucose and insulin data were analyzed using ANOVA for a crossover design, while NSC concentrations were analyzed using ANOVA with repeated measures, with treatment, period and
Disappearance of phytate phosphorus is not altered by addition of phytase to equine diets
Unlike in other monogastric species, there is little evidence to show that addition of phytase to equine diets increases P availability. Results from a preliminary study indicated greater than 90% disappearance of phytate P, regardless of whether phytase was incorporated into the diet or not. As no other equine studies examined the disappearance of phytate P in horses (both with and without addition of phytase), this study was performed to determine if the results could be duplicated. Six mature geldings were used in a duplicated 3x3 Latin square study design in which all horses received a control diet (C) exceeding NRC 2007 P requirements (0.264% P), a low P diet (LP; 0.141% P), and a low P diet with added phytase (LP+Phy; 0.134% P). The diets, fed at 1.75% of BW, were in the form of a pelleted complete feed to ensure precise intake of P and phytase. The pellets were soaked prior to feeding. Due to the novelty of a complete feed and to minimize variation in P intake prior to treatment assignment, all horses were adapted to the C diet for two weeks prior to treatment assignment. Horses were pair-matched by breed, age, and weight, and then pairs were randomly assigned to treatments so two horses were on each treatment at a time and all horses experienced each treatment for two weeks. At the end of each two-week interval, total collections of feces and urine were obtained for three days and representative samples were retained for analysis of total P in feed, urine, and feces, and phytate P in the feed and feces, in order to determine total P and phytate P intake, output, and disappearance. As expected, intake of phytate P and free P was greater on the control diet (P<0.0001). Urinary P output (g) did not differ amongst groups (P¼0.14). Total fecal P (g) was higher in C
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markers (PGE2, TNF-a, IFN-g). However, plasma eicosapentaenoic acid concentrations were higher in horses on the SOY diet (0.45 0.07 percent of total plasma lipid) than horses on FLAX and ALG (P< 0.05), and plasma a-linolenic acid was altered in response to treatment (P< 0.05) with horses on FLAX having the greatest percentage. Serum interleukin-10 concentrations were lower in SOY than in ALG (P< 0.05). The results of this study indicate that mature exercising horses free from osteoarthritis do not exhibit physiological anti-inflammatory benefits when supplemented with a low dose of omega-3 fatty acids over a 21-d period. This study suggests a higher dose of DHA may need to be offered. Alternatively, if feeding DHA at an amount lower than 30 to 35 g/d, supplementation longer than 21-d may be required to observe potential differences in plasma FA concentrations. To our knowledge, this is the first study to supplement n-3 FA in the form of DHA-rich microalgae (DRM) to exercising horses. As nothing is known about potential differences in bioavailability of a DRM source of DHA in the horse, additional research is needed with an amount greater than 28.4 g/d for a 21-d period of DHA to validate the effects of a DRM DHA source on metabolic effects of DHA in the horse.
sequence of treatment as the main effects, and horse within sequence as the subject. In Exp. 1, mean pasture NSC concentrations at the start of grazing for DAY was 14.3 0.8% and increased (P<0.01) to a peak value of 18.3 0.8% 10 hr later, and then decreased (P<0.001) to 11.8 1.1% by 0700 the next morning. In Exp. 2, mean NSC concentrations was 16.8 1.7% at the start of grazing for DAY and remained unchanged until 0300 the next morning, when it decreased (P <0.05) to 10.9 1.7% and remained unchanged for the duration of the NIGHT grazing. In both experiments, logPI was higher (P<0.05) in NIGHT than DAY, and in Exp 2. NIGHT was also higher (P<0.05) than CTRL. In Exp. 1, mean logAUCI was greater (P<0.01) for CTRL than DAYand NIGHT. In Exp. 2, logAUCI for DAY was less (P<0.05) than CRTL and NIGHT. Glucose concentrations were not affected by treatment. These data suggest that while continuous grazing results in elevated insulin concentrations throughout the day, the highest insulin concentrations are achieved in horses turned out in the evening. Horses with metabolic conditions should avoid turnout at these times.
Glucose and insulin concentrations in restricted pasture-fed horses
E.D. Lamprecht 1, B.D. Nielsen 2, and C.I. Robison 2 1 Cargill, Incorporated, Elk River, MN 55330, 2 Department of Animal Science, Michigan State University, East Lansing, MI, USA 48824-1225
S.E. Pratt-Phillips, C. Wycoff, C. Sykes, J. Kutzner-Mulligan, and P.D. Siciliano Department of Animal Science, North Carolina State University, Raleigh, NC 27695 Two experiments were conducted to determine the effect of 10-h restricted grazing during the day-light (DAY) and night-time (NIGHT), compared to continuous grazing (CTRL), on changes in blood glucose and insulin concentrations. Experiments 1 and 2 were conducted during the spring and subsequent fall, respectively. For both experiments, a completely randomized crossover design was used. Twelve mature stock-type geldings (583 48 kg) were randomly assigned to one of three treatments (DAY, NIGHT or CTRL) for a period of 10 d. Following each 10-d period, horses were assigned to a new treatment so that all horses were exposed to all treatments. For the DAY group, grazing began at 1000 h and ended at 1800 h (except for Period 1 of Exp. 1 where grazing was from 1100 h – 2100 h). For the NIGHT group, grazing began at 2100 h and ended at 0700 h. Pasture consisted of predominantly tall fescue. On day 9, horses were fitted with jugular catheters and blood samples were collected hourly for a 24-h period. If a horse was at pasture, pasture samples were also collected every other hour and analyzed for NSC by wet chemistry. Plasma glucose and serum insulin concentrations were determined by spectroscopy and RIA, respectively. Area under the curve for glucose (AUCG) and insulin (AUCI), and peak glucose (PG) and insulin (PI) were determined, and insulin values were logged to obtain a normal distribution of the data. Glucose and insulin data were analyzed using ANOVA for a crossover design, while NSC concentrations were analyzed using ANOVA with repeated measures, with treatment, period and
Disappearance of phytate phosphorus is not altered by addition of phytase to equine diets
Unlike in other monogastric species, there is little evidence to show that addition of phytase to equine diets increases P availability. Results from a preliminary study indicated greater than 90% disappearance of phytate P, regardless of whether phytase was incorporated into the diet or not. As no other equine studies examined the disappearance of phytate P in horses (both with and without addition of phytase), this study was performed to determine if the results could be duplicated. Six mature geldings were used in a duplicated 3x3 Latin square study design in which all horses received a control diet (C) exceeding NRC 2007 P requirements (0.264% P), a low P diet (LP; 0.141% P), and a low P diet with added phytase (LP+Phy; 0.134% P). The diets, fed at 1.75% of BW, were in the form of a pelleted complete feed to ensure precise intake of P and phytase. The pellets were soaked prior to feeding. Due to the novelty of a complete feed and to minimize variation in P intake prior to treatment assignment, all horses were adapted to the C diet for two weeks prior to treatment assignment. Horses were pair-matched by breed, age, and weight, and then pairs were randomly assigned to treatments so two horses were on each treatment at a time and all horses experienced each treatment for two weeks. At the end of each two-week interval, total collections of feces and urine were obtained for three days and representative samples were retained for analysis of total P in feed, urine, and feces, and phytate P in the feed and feces, in order to determine total P and phytate P intake, output, and disappearance. As expected, intake of phytate P and free P was greater on the control diet (P<0.0001). Urinary P output (g) did not differ amongst groups (P¼0.14). Total fecal P (g) was higher in C