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Metabolic effects of psyllium supplementation in horses grazing rapidly growing cool-season grass
Abstracts / Journal of Equine Veterinary Science 33 (2013) 321-399
showed the best fit to the data available (DMD ¼ 70.54715 – 0.38490 NDF + 0.40783 CP; P< 0.001; adjusted R2 ¼ 0.5552). Regression using data from growing horses indicated DMD could not be predicted by diet characteristics; however, this result may be influenced by the small data set (n ¼ 13). Stepwise regression of 15 studies with complete data was used to establish useful predictors for DMD, NDFD, ADFD, and CPD. Significant terms in the regression analysis for DMD included horse weight, breed, NDF, CP, and the study (P< 0.0001, adjusted R2 ¼ 0.8570). Significant terms for NDFD included horse weight, breed, type of forage (cool season legume, cool season grass, mixed forages, forage fed with grain, and warm season grasses), forage processing (pelleted, long stem, or mixed), NDF, NDF-ADF, ADF as a percentage of NDF, CP, and the study (P ¼ 0.012, adjusted R2 ¼ 0.5594). Significant terms for ADFD included type of forage, DM intake, horse weight, breed, NDF, NDF-ADF, CP, and the study (P< 0.0001, adjusted R2 ¼ 0.7607). Significant terms for CPD included type of forage, DM intake, ADF as a percentage of NDF, CP, and the study (P< 0.0001, adjusted R2 ¼ 0.7395). However, multicollinearity is expected in these models, and studies may need to be weighted to account for study variability due to methods. Predictive models of DMD, NDFD, ADFD, and CPD need to be developed further before practical application.
341
fecal particle length in the day 7 samples (Table 1; P¼0.93) or over the whole week (P¼0.3). Diet had no effect on intake time (LH¼110 min, CH¼115 min, SEM¼22; P¼0.86), PCV (LH¼42.1%, CH¼42.0%, SEM¼1.3; P¼0.88), or TS (LH¼7.0, CH¼7.0, SEM¼0.7; P¼0.74), although both PCV and TS increased over the 3-hr sampling period (P<0.01). Water consumption (LH¼22.6 kg/d, CH¼22.4 kg/d, SEM¼1.2) and fecal dry matter (22.8% for both groups, SEM¼0.2) did not differ between treatments (P¼0.9). Chopping hay did not have an impact on measured variables so its potential role in helping to maintain lower body temperature during endurance exercise remains unclear. Interestingly, only w10% of the fecal particles did not pass through the sieve of 2.36 mm and over 40% passed through a sieve of 150 mm, suggesting a marked reduction in particle size during the digestive process regardless of original intake length.
Table 1 Mean percent (and SEM) of fecal particles collected on day 7 according to size as measured using a wet sieve procedure Size
Chopped hay
Long hay
SEM
> 2.36 mm > 1.18 mm < 2.36 mm > 600 mm < 1.18 mm > 300 mm< 600 mm > 150 mm< 300 mm Less than 150 mm
10.0% 15.7% 14.7% 10.8% 6.8% 42.2%
9.5% 14.5% 14.5% 10.3% 6.5% 44.9%
0.5% 0.5% 0.5% 0.5% 0.5% 1.0%
Chopping hay before feeding does not influence fecal particle size, blood variables, or water intake in threeyear-old Arabians. R.A. LeCompte 1, B.D. Nielsen 1, C.I. Robison 1, and P. Harris 2 1 Department of Animal Science, Michigan State University, East Lansing, MI, USA 48824-1225, 2 WALTHAM Centre for Pet Nutrition, Leics, UK Previous work suggested that the form in which roughage is presented to horses (chopped versus long stem) may play a role in thermoregulation during prolonged exercise, potentially by influencing the dynamics of water release during digestion of hay particles. Hindgut particle size, therefore, may be an important factor, but the effect of chopping on this has not been evaluated.This study aimed to determine if chopping hay affects fecal particle size and whether this influences packed cell volume (PCV), plasma total solids (TS), or fecal water and particle length.Six 3-yrold Arabians in light training were divided into two groups of three horses for a 4-wk study. All horses were in good general and dental health. Each group was fed either long-stem alfalfa hay (LH) or the same hay chopped (CH; range 1 to 6 cm particle length) during wk 1. During wk 2, treatments were reversed, allowing acclimation. During wk 3 and 4, horses were given the same diets as wk 1 and 2, respectively. On day 7 (end wk 3 and 4 respectively), water consumption was measured over a 48-hr period, feed intake time was recorded, and PCV plus TS were measured at 0, 30, 60, 90, 120, 150, and 180 min post-hay feeding. Fecal samples were collected immediately after voiding each morning during wk 3 and 4 to determine fecal water and particle size. There was no effect of diet on
Metabolic effects of psyllium supplementation in horses grazing rapidly growing cool-season grass J.L. Rohrs, S.M. Moreaux, R.A. Frost, J. Weeding, and J.G. Berardinelli Department of Animal and Range Sciences, Montana State University, Bozeman, MT, 59717 Digestion of non-structural carbohydrates (NSC) from cool season pasture grasses can result in increased adiposity, risk of insulin resistance, and laminitis in horses [1]. Research has shown that lowering blood glucose levels and increasing insulin sensitivity will reduce the risk of laminitis and associated diseases [2]. Supplementing horses with psyllium reduces blood glucose and insulin concentrations in horses that are meal fed [3]. The objective of this study was to evaluate the effects of psyllium supplementation in horses grazing rapidly growing cool season grass. Eleven lightbreed stock horses (7 mares, 4 geldings, Age 13.5 2.5; mean SD) were individually confined in dry lots overnight and strip grazed for 8 hours daily for 30 days. Psyllium-supplemented horses received (n ¼ 6) 180 g of psyllium daily. All horses received an isocaloric protein supplement. Forage intake for each horse was calculated using a previously published equation [4]. Forage was analyzed for nutrient content every other week. Changes in metabolic characteristics were assessed by assay of glucose, insulin, leptin and adiponectin concentrations in blood samples collected on days 0, 8, 15, 22, and 29 at
342
Abstracts / Journal of Equine Veterinary Science 33 (2013) 321-399
0700, 0800, 0900, 1100, 1300, and 1500 hours. Psyllium supplementation lowered glucose (P<0.0001) concentrations, glucose AUC (P<0.0001), insulin AUC (P ¼0.0067), and increased time to peak glucose (P ¼0.0478).There was a treatment by sex interaction for insulin (P ¼0.0101), and peak insulin (P ¼0.0163) concentrations, glucose AUC (P ¼0.0253), and insulin AUC (P ¼0.0129). These variables were lowered to a greater extent in geldings than in mares. Higher NSC intake resulted in higher peak insulin (P ¼0.0398) in all horses. Older horses had higher peak insulin (P 0.0091), decreased time to peak glucose (P<0.0001) and decreased time to peak insulin (P 0.0005All characteristics of glucose and insulin decreased (P 0.0154) over the 30 day interval spent grazing pasture. These results indicate that supplementing psyllium in horses grazing cool season grasses lowered systemic glucose and insulin concentrations and these effects may reduce the risk of metabolic diseases, such as laminitis, in horses consuming NSCs. However, systemic glucose and insulin concentrations were effected to a greater extent in males than females. References [1] Frank N. Endocrinopathic laminitis, obesity-associated laminitis, and pasture-associated laminitis. Am Assoc Equine Practitioners Proc 2008;54:341-6. [2] DeLatt MA, McGowan CM, Sillence MN, Pollitt CC. Equine laminitis: induced by 48 h hyperinsulinemia in Standardbred horses. Equine Vet J 2010;42(2):129-35. [3] Moreaux SJJ, Nichols JL, Bowman JGP, Hatfield PG. Psyllium lowers blood glucose and insulin concentrations in horses. J Equine Vet Sci 2011;31:160-5. [4] Dowler LE, Sicilliano PD. Prediction of Hourly Pasture Dry Matter Intake in Horses. J Equine Vet Sci 2009;29:354-5 (abstract).
Comparison of krill oil and fish oil supplementation on serum and tissue fatty acid profiles in horses L.E. Bowen 1, 3, H.S. Spooner 2, J.L. Zambito 1, and K.M. Barnes 1 1 Animal & Nutritional Sciences, West Virginia University, Morgantown, WV, 26506, 2 Agribusiness & Agriscience, Middle Tennessee State University, Murfreesboro, TN, 37129, 3 Current address: Agricultural Sciences, West Texas A&M University, Canyon, TX, 79016 Dietary fat supplementation is commonly utilized to increase caloric density and/or improve fat utilization during low-intensity exercise; however, oil (fat) source may play a role in metabolic function. Fish oil (FO) supplementation, high in omega-3s, is commonly utilized in horses, and has been shown to increase plasma docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) concentrations compared to corn oil. [1] In human and rodent models, current research suggests krill oil (KO) may be superior to FO as the omega-3s are provided in phospholipid form, which could impact their usefulness. [2] Specifically, we hypothesize that: 1) horses fed KO will have greater plasma and tissue incorporations of EPA and DHA than horses receiving FO, and 2) horses fed KO will have lower serum triglyceride (TG) and plasma non-
esterified fatty acid (NEFA) concentrations than FO-fed horses. Seven mature, stock-type horses of moderate body condition (BCS 60.5) were randomly assigned to FO (menhaden; n¼4) or KO (n¼3) supplementation. Supplementation was provided at 324 mg/kg BW/d, split into two doses top-dressed over concentrate for 42d. Prior to the study (d0), at d21, and d42, jugular blood samples and biopsies from the middle gluteal muscle were obtained and analyzed for TG and NEFA concentration and fatty acid profiles. Serum TG decreased from 161.813.9 mg/L at d0 to 83.713.9 mg/L at d42, although no diet difference was observed. Similarly, plasma NEFA decreased from 0.400.04 mEq/L at d0 to 0.080.04 mEq/L at d42. Relative fatty acid profiles were different due to diet only at d42 in serum EPA (FO: 1.410.62%; KO: 5.040.72%) and in tissue lignoceric acid (C24:0; FO: 0.000.02; KO: 0.100.02). However, in serum, for both diets, relative percentage of palmitic acid (C16:0) increased from 16.052.26% at d0 to 24.352.26% on d42, while alpha-lenolenic acid (ALA; C18:3n3) decreased from 2.490.41% to 0.610.41%. In muscle, increases from d0 to d42 were observed for eicosatrienoic acid (C20:3n6; 0.250.14% to 0.630.14%), EPA (0.070.24% to 1.880.24%), and DHA (0.070.24% to 1.930.24%). Contrary to our hypothesis, these results suggest that KO and FO are similar in their ability to alter blood lipid properties. While KO increased serum EPA to a greater extent than FO, this was not reflected in tissue where the two were similar in their ability to alter fatty acid profiles. Thus, based on these results and given substantially higher cost, inclusion of KO in the equine diet, as an alternative to FO, does not currently seem warranted.
References [1] O’Connor CI, Lawrence LM, Hayes S. Dietary fish oil supplementation affects serum fatty acid concentrations in horses. J. Anim. Sci 2007; 9(83):2183. [2] Ierna M, Kerr A, Scales H, et al. Supplementation of diet with krill oil protects against experimental rheumatoid arthritis. BMC Musculoskel.Disorders 2010;11:136.
The availability of dietary phosphorus to long yearlings and mature horses A.L. Fowler, L.A. Strasinger, T.L. Hansen, B.E. Davis, S.H. Hayes, and L.M. Lawrence Department of Animal and Food Sciences, University of Kentucky, Lexington, KY Phosphorus (P) is an increasing environmental concern in the agricultural industry due to its eutrophication effect in water bodies. When horses are fed high concentrate diets, they are also usually ingesting a high amount of P. The excess P that the horse does not absorb is excreted in the feces. While some of the P can be returned to the soil and used for plant growth, some can leach into water bodies. The NRC uses a P digestibility of 45% for P in growing horse diets, but this is related to P source, not the potential for the horse to absorb dietary P. In diets without inorganic P, the estimate for the true P digestibility is 35%. If the true digestibility of P is greater than NRC estimates, the amount of P fed and amount excreted
showed the best fit to the data available (DMD ¼ 70.54715 – 0.38490 NDF + 0.40783 CP; P< 0.001; adjusted R2 ¼ 0.5552). Regression using data from growing horses indicated DMD could not be predicted by diet characteristics; however, this result may be influenced by the small data set (n ¼ 13). Stepwise regression of 15 studies with complete data was used to establish useful predictors for DMD, NDFD, ADFD, and CPD. Significant terms in the regression analysis for DMD included horse weight, breed, NDF, CP, and the study (P< 0.0001, adjusted R2 ¼ 0.8570). Significant terms for NDFD included horse weight, breed, type of forage (cool season legume, cool season grass, mixed forages, forage fed with grain, and warm season grasses), forage processing (pelleted, long stem, or mixed), NDF, NDF-ADF, ADF as a percentage of NDF, CP, and the study (P ¼ 0.012, adjusted R2 ¼ 0.5594). Significant terms for ADFD included type of forage, DM intake, horse weight, breed, NDF, NDF-ADF, CP, and the study (P< 0.0001, adjusted R2 ¼ 0.7607). Significant terms for CPD included type of forage, DM intake, ADF as a percentage of NDF, CP, and the study (P< 0.0001, adjusted R2 ¼ 0.7395). However, multicollinearity is expected in these models, and studies may need to be weighted to account for study variability due to methods. Predictive models of DMD, NDFD, ADFD, and CPD need to be developed further before practical application.
341
fecal particle length in the day 7 samples (Table 1; P¼0.93) or over the whole week (P¼0.3). Diet had no effect on intake time (LH¼110 min, CH¼115 min, SEM¼22; P¼0.86), PCV (LH¼42.1%, CH¼42.0%, SEM¼1.3; P¼0.88), or TS (LH¼7.0, CH¼7.0, SEM¼0.7; P¼0.74), although both PCV and TS increased over the 3-hr sampling period (P<0.01). Water consumption (LH¼22.6 kg/d, CH¼22.4 kg/d, SEM¼1.2) and fecal dry matter (22.8% for both groups, SEM¼0.2) did not differ between treatments (P¼0.9). Chopping hay did not have an impact on measured variables so its potential role in helping to maintain lower body temperature during endurance exercise remains unclear. Interestingly, only w10% of the fecal particles did not pass through the sieve of 2.36 mm and over 40% passed through a sieve of 150 mm, suggesting a marked reduction in particle size during the digestive process regardless of original intake length.
Table 1 Mean percent (and SEM) of fecal particles collected on day 7 according to size as measured using a wet sieve procedure Size
Chopped hay
Long hay
SEM
> 2.36 mm > 1.18 mm < 2.36 mm > 600 mm < 1.18 mm > 300 mm< 600 mm > 150 mm< 300 mm Less than 150 mm
10.0% 15.7% 14.7% 10.8% 6.8% 42.2%
9.5% 14.5% 14.5% 10.3% 6.5% 44.9%
0.5% 0.5% 0.5% 0.5% 0.5% 1.0%
Chopping hay before feeding does not influence fecal particle size, blood variables, or water intake in threeyear-old Arabians. R.A. LeCompte 1, B.D. Nielsen 1, C.I. Robison 1, and P. Harris 2 1 Department of Animal Science, Michigan State University, East Lansing, MI, USA 48824-1225, 2 WALTHAM Centre for Pet Nutrition, Leics, UK Previous work suggested that the form in which roughage is presented to horses (chopped versus long stem) may play a role in thermoregulation during prolonged exercise, potentially by influencing the dynamics of water release during digestion of hay particles. Hindgut particle size, therefore, may be an important factor, but the effect of chopping on this has not been evaluated.This study aimed to determine if chopping hay affects fecal particle size and whether this influences packed cell volume (PCV), plasma total solids (TS), or fecal water and particle length.Six 3-yrold Arabians in light training were divided into two groups of three horses for a 4-wk study. All horses were in good general and dental health. Each group was fed either long-stem alfalfa hay (LH) or the same hay chopped (CH; range 1 to 6 cm particle length) during wk 1. During wk 2, treatments were reversed, allowing acclimation. During wk 3 and 4, horses were given the same diets as wk 1 and 2, respectively. On day 7 (end wk 3 and 4 respectively), water consumption was measured over a 48-hr period, feed intake time was recorded, and PCV plus TS were measured at 0, 30, 60, 90, 120, 150, and 180 min post-hay feeding. Fecal samples were collected immediately after voiding each morning during wk 3 and 4 to determine fecal water and particle size. There was no effect of diet on
Metabolic effects of psyllium supplementation in horses grazing rapidly growing cool-season grass J.L. Rohrs, S.M. Moreaux, R.A. Frost, J. Weeding, and J.G. Berardinelli Department of Animal and Range Sciences, Montana State University, Bozeman, MT, 59717 Digestion of non-structural carbohydrates (NSC) from cool season pasture grasses can result in increased adiposity, risk of insulin resistance, and laminitis in horses [1]. Research has shown that lowering blood glucose levels and increasing insulin sensitivity will reduce the risk of laminitis and associated diseases [2]. Supplementing horses with psyllium reduces blood glucose and insulin concentrations in horses that are meal fed [3]. The objective of this study was to evaluate the effects of psyllium supplementation in horses grazing rapidly growing cool season grass. Eleven lightbreed stock horses (7 mares, 4 geldings, Age 13.5 2.5; mean SD) were individually confined in dry lots overnight and strip grazed for 8 hours daily for 30 days. Psyllium-supplemented horses received (n ¼ 6) 180 g of psyllium daily. All horses received an isocaloric protein supplement. Forage intake for each horse was calculated using a previously published equation [4]. Forage was analyzed for nutrient content every other week. Changes in metabolic characteristics were assessed by assay of glucose, insulin, leptin and adiponectin concentrations in blood samples collected on days 0, 8, 15, 22, and 29 at
342
Abstracts / Journal of Equine Veterinary Science 33 (2013) 321-399
0700, 0800, 0900, 1100, 1300, and 1500 hours. Psyllium supplementation lowered glucose (P<0.0001) concentrations, glucose AUC (P<0.0001), insulin AUC (P ¼0.0067), and increased time to peak glucose (P ¼0.0478).There was a treatment by sex interaction for insulin (P ¼0.0101), and peak insulin (P ¼0.0163) concentrations, glucose AUC (P ¼0.0253), and insulin AUC (P ¼0.0129). These variables were lowered to a greater extent in geldings than in mares. Higher NSC intake resulted in higher peak insulin (P ¼0.0398) in all horses. Older horses had higher peak insulin (P 0.0091), decreased time to peak glucose (P<0.0001) and decreased time to peak insulin (P 0.0005All characteristics of glucose and insulin decreased (P 0.0154) over the 30 day interval spent grazing pasture. These results indicate that supplementing psyllium in horses grazing cool season grasses lowered systemic glucose and insulin concentrations and these effects may reduce the risk of metabolic diseases, such as laminitis, in horses consuming NSCs. However, systemic glucose and insulin concentrations were effected to a greater extent in males than females. References [1] Frank N. Endocrinopathic laminitis, obesity-associated laminitis, and pasture-associated laminitis. Am Assoc Equine Practitioners Proc 2008;54:341-6. [2] DeLatt MA, McGowan CM, Sillence MN, Pollitt CC. Equine laminitis: induced by 48 h hyperinsulinemia in Standardbred horses. Equine Vet J 2010;42(2):129-35. [3] Moreaux SJJ, Nichols JL, Bowman JGP, Hatfield PG. Psyllium lowers blood glucose and insulin concentrations in horses. J Equine Vet Sci 2011;31:160-5. [4] Dowler LE, Sicilliano PD. Prediction of Hourly Pasture Dry Matter Intake in Horses. J Equine Vet Sci 2009;29:354-5 (abstract).
Comparison of krill oil and fish oil supplementation on serum and tissue fatty acid profiles in horses L.E. Bowen 1, 3, H.S. Spooner 2, J.L. Zambito 1, and K.M. Barnes 1 1 Animal & Nutritional Sciences, West Virginia University, Morgantown, WV, 26506, 2 Agribusiness & Agriscience, Middle Tennessee State University, Murfreesboro, TN, 37129, 3 Current address: Agricultural Sciences, West Texas A&M University, Canyon, TX, 79016 Dietary fat supplementation is commonly utilized to increase caloric density and/or improve fat utilization during low-intensity exercise; however, oil (fat) source may play a role in metabolic function. Fish oil (FO) supplementation, high in omega-3s, is commonly utilized in horses, and has been shown to increase plasma docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) concentrations compared to corn oil. [1] In human and rodent models, current research suggests krill oil (KO) may be superior to FO as the omega-3s are provided in phospholipid form, which could impact their usefulness. [2] Specifically, we hypothesize that: 1) horses fed KO will have greater plasma and tissue incorporations of EPA and DHA than horses receiving FO, and 2) horses fed KO will have lower serum triglyceride (TG) and plasma non-
esterified fatty acid (NEFA) concentrations than FO-fed horses. Seven mature, stock-type horses of moderate body condition (BCS 60.5) were randomly assigned to FO (menhaden; n¼4) or KO (n¼3) supplementation. Supplementation was provided at 324 mg/kg BW/d, split into two doses top-dressed over concentrate for 42d. Prior to the study (d0), at d21, and d42, jugular blood samples and biopsies from the middle gluteal muscle were obtained and analyzed for TG and NEFA concentration and fatty acid profiles. Serum TG decreased from 161.813.9 mg/L at d0 to 83.713.9 mg/L at d42, although no diet difference was observed. Similarly, plasma NEFA decreased from 0.400.04 mEq/L at d0 to 0.080.04 mEq/L at d42. Relative fatty acid profiles were different due to diet only at d42 in serum EPA (FO: 1.410.62%; KO: 5.040.72%) and in tissue lignoceric acid (C24:0; FO: 0.000.02; KO: 0.100.02). However, in serum, for both diets, relative percentage of palmitic acid (C16:0) increased from 16.052.26% at d0 to 24.352.26% on d42, while alpha-lenolenic acid (ALA; C18:3n3) decreased from 2.490.41% to 0.610.41%. In muscle, increases from d0 to d42 were observed for eicosatrienoic acid (C20:3n6; 0.250.14% to 0.630.14%), EPA (0.070.24% to 1.880.24%), and DHA (0.070.24% to 1.930.24%). Contrary to our hypothesis, these results suggest that KO and FO are similar in their ability to alter blood lipid properties. While KO increased serum EPA to a greater extent than FO, this was not reflected in tissue where the two were similar in their ability to alter fatty acid profiles. Thus, based on these results and given substantially higher cost, inclusion of KO in the equine diet, as an alternative to FO, does not currently seem warranted.
References [1] O’Connor CI, Lawrence LM, Hayes S. Dietary fish oil supplementation affects serum fatty acid concentrations in horses. J. Anim. Sci 2007; 9(83):2183. [2] Ierna M, Kerr A, Scales H, et al. Supplementation of diet with krill oil protects against experimental rheumatoid arthritis. BMC Musculoskel.Disorders 2010;11:136.
The availability of dietary phosphorus to long yearlings and mature horses A.L. Fowler, L.A. Strasinger, T.L. Hansen, B.E. Davis, S.H. Hayes, and L.M. Lawrence Department of Animal and Food Sciences, University of Kentucky, Lexington, KY Phosphorus (P) is an increasing environmental concern in the agricultural industry due to its eutrophication effect in water bodies. When horses are fed high concentrate diets, they are also usually ingesting a high amount of P. The excess P that the horse does not absorb is excreted in the feces. While some of the P can be returned to the soil and used for plant growth, some can leach into water bodies. The NRC uses a P digestibility of 45% for P in growing horse diets, but this is related to P source, not the potential for the horse to absorb dietary P. In diets without inorganic P, the estimate for the true P digestibility is 35%. If the true digestibility of P is greater than NRC estimates, the amount of P fed and amount excreted