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Assessment of the effect of dietary particle size on gastrointestinal permeability
Abstracts / Journal of Equine Veterinary Science 52 (2017) 76e95
of Co daily. Feces and urine were collected to evaluate fiber digestion and mineral digestibility. Although there was a trend showing a cubic increase in DM digestibility (P ¼ 0.06), there was no effect of Co supplementation on the digestibility of neutral detergent fiber, acid detergent fiber, or lignin. There was an inverse linear relationship between supplemental Co concentration and serum cobalamin levels (P ¼ 0.003), while folate levels were unaffected. Cobalt digestibility increased with increasing dietary Co (P ¼ 0.04). Additionally, serum Co differed (P < 0.01) with a mean of 4.7 mg/mL for the high treatment and 0.8 mg/mL for the control treatment. Graphing Co intake against Co retention reveals an intercept of 0.39 mg/kg of DM, which is in close proximity to the 0.46 mg (0.05 mg Co/kg of DM when average DMI is 9.3 kg) as suggested by the 2007 NRC. This suggests that the reduction in Co requirement from the 1989 NRC to the 2007 NRC was warranted. This study also suggests normal dietary supplementation with Co, even when provided substantially above the 2007 NRC requirement, will not result in Co concentrations resulting in health concerns or serum concentrations near the thresholds established by some racing jurisdictions. Key Words: cobalt, fiber, mineral
104 Assessment of the effect of dietary particle size on gastrointestinal permeability S.L. Lapinskas*, K.J. Harvatine, P. Ochonski, W.B. Staniar The Pennsylvania State University, University Park, PA, USA The epithelial layer of the gastrointestinal tract (GIT) acts as a barrier between the body and the lumen. Compromising this barrier can lead to passage of toxins and microbes into the body. It was hypothesized that diets with decreasing particle size would result in increased GIT permeability. Eight geldings (528 ± 54 kg BW) ranging from 3 to 15 yr were used in a Latin Square design. Four dietary treatments fed at 2% BW were 100% hay (HA), 40% hay and 55% whole oats (HO), 40% hay, 27.5% whole oats, and 27.5% pellets (HOP), and 40% hay and 55% pellets (HP). Differences in dietary particle size are clarified by the % feed particles <1.18 mm in the HA, HO, HOP, and HP diets (1, 5, 33, and 60%; respectively). Pellets were formulated to have similar nutrient makeup to the whole oats. To meet nutrient requirements HO, HP, and HOP diets had a balancer pellet added at 5%. Treatments were divided into 4 14 d periods; each proceeded by a 14 d hay only washout period. The last period was followed by a 14 d washout and a 7 d ulcer induction as a positive control. Previously validated sugar absorption tests were used to measure GIT permeability at the end of each period. Mannitol, sucrose, lactulose, and sucralose were administered orally in solution and total urine was collected for 24 h. Pooled 24 h urine samples were preserved with 10% thymol solution and frozen at 20 C until analyzed for % sugar excretion (Table 1). A previously validated alditol acetate derivatization was used and sugar was quantified using gas
85
chromatography with flame ionization detection. A mixed ANOVA was used to investigate the differences due to the fixed effects of diet and period. Differences were defined at P < 0.05. There was an effect of diet on % sugar excretion for all sugars, characterized by the HP group generally having a higher permeability. This indicates that diets with higher % of smaller feed particles may result in increased GIT permeability. Permeability following ulcer induction was lower than treatment or washout periods. This challenges the effective use of permeability, measured as % sugar excretion, in determining clinical ulceration. Key Words: particle size, permeability, oats
105 Digestibility of different diets after a weight gain protocol in Standardbreds, Andalusians, and mixed-breed ponies S.J. Potter 1, N.J. Bamford 1, P.A. Harris 2, S.R. Bailey*1 1 University of Melbourne, Melbourne, Victoria, Australia; 2 Waltham Centre for Pet Nutrition, Waltham on the Wolds, Leicestershire, United Kingdom Ponies and certain horse breeds tend to gain weight easily and are often called ‘easy keepers’. It is unknown whether these breed/type differences could be due to nutrient digestibility differences. This study assessed digestibility in 2 similar-sized horse breeds (one insulin sensitive and one relatively insulin resistant) and mixed-breed ponies after a 20wks weight gain protocol using different diets. Eight Standardbred horses (4e20yrs), 8 mixed-breed ponies (5e16yrs) and 8 Andalusian/ Andalusian-cross horses (3e13yr) with moderate initial BCS were evaluated. Over 2 study periods, 3 animals of each breed were fed for maintenance, (hay plus a ration balancer, oaten chaff and soybean hull pellets: control); 2 crossed to the weight-gain groups for the second period, and one of each breed crossed to the maintenance group after re-attaining moderate BCS. Four animals of each breed were fed the control diet plus a rising plane of nutrition up to 201% of maintenance energy requirements using either a high fat diet (HF: added fat/ oil increasing to 200g/100 kg BW: Lucerne chaff, canola oil plus granulated vegetable fat) or an isocaloric high grain diet (HG: HF diet with oil/fat replaced by micronized maize progressively increasing to 455g/100kg BW). After 20 wk, those on the weight gain diets had all significantly increased BCS to 7/9. Hay was available ad libitum except for the collection period when given 2.5% BW DM. Apparent digestibility of gross energy (GE), fat (CF) and protein (CP) as well as starch and neutral detergent fiber (NDF) digestibilities were determined, and fecal pH plus DM monitored, during a 24hr total fecal output collection at the end of the study. During the collection period, feed consumption corrected for BW was similar between the breeds. There was no effect of breed/diet on fecal pH or DM. There were no
Table 1 Percent sugar marker excretion for total 24-h urine collection Sugar marker
Sugar dose (mg/kg BW)
Percent excretion HA
Mannitol Sucralose Lactulose Sucrose
40 200 70 70
1.6 0.8 2.2 2.8
P-value HO
± ± ± ±
0.1a 0.4ab 0.5a 1.1ab
2.1 0.8 2.3 2.4
HOP ± ± ± ±
0.6b 0.3ab 0.7ab 0.7a
2.2 0.5 2.0 2.0
± ± ± ±
HP 0.5b 0.2a 0.6a 0.4a
2.6 1.1 2.9 3.4
± ± ± ±
0.5b 0.4b 0.5b 0.4b
<0.001 <0.05 <0.05 <0.05
of Co daily. Feces and urine were collected to evaluate fiber digestion and mineral digestibility. Although there was a trend showing a cubic increase in DM digestibility (P ¼ 0.06), there was no effect of Co supplementation on the digestibility of neutral detergent fiber, acid detergent fiber, or lignin. There was an inverse linear relationship between supplemental Co concentration and serum cobalamin levels (P ¼ 0.003), while folate levels were unaffected. Cobalt digestibility increased with increasing dietary Co (P ¼ 0.04). Additionally, serum Co differed (P < 0.01) with a mean of 4.7 mg/mL for the high treatment and 0.8 mg/mL for the control treatment. Graphing Co intake against Co retention reveals an intercept of 0.39 mg/kg of DM, which is in close proximity to the 0.46 mg (0.05 mg Co/kg of DM when average DMI is 9.3 kg) as suggested by the 2007 NRC. This suggests that the reduction in Co requirement from the 1989 NRC to the 2007 NRC was warranted. This study also suggests normal dietary supplementation with Co, even when provided substantially above the 2007 NRC requirement, will not result in Co concentrations resulting in health concerns or serum concentrations near the thresholds established by some racing jurisdictions. Key Words: cobalt, fiber, mineral
104 Assessment of the effect of dietary particle size on gastrointestinal permeability S.L. Lapinskas*, K.J. Harvatine, P. Ochonski, W.B. Staniar The Pennsylvania State University, University Park, PA, USA The epithelial layer of the gastrointestinal tract (GIT) acts as a barrier between the body and the lumen. Compromising this barrier can lead to passage of toxins and microbes into the body. It was hypothesized that diets with decreasing particle size would result in increased GIT permeability. Eight geldings (528 ± 54 kg BW) ranging from 3 to 15 yr were used in a Latin Square design. Four dietary treatments fed at 2% BW were 100% hay (HA), 40% hay and 55% whole oats (HO), 40% hay, 27.5% whole oats, and 27.5% pellets (HOP), and 40% hay and 55% pellets (HP). Differences in dietary particle size are clarified by the % feed particles <1.18 mm in the HA, HO, HOP, and HP diets (1, 5, 33, and 60%; respectively). Pellets were formulated to have similar nutrient makeup to the whole oats. To meet nutrient requirements HO, HP, and HOP diets had a balancer pellet added at 5%. Treatments were divided into 4 14 d periods; each proceeded by a 14 d hay only washout period. The last period was followed by a 14 d washout and a 7 d ulcer induction as a positive control. Previously validated sugar absorption tests were used to measure GIT permeability at the end of each period. Mannitol, sucrose, lactulose, and sucralose were administered orally in solution and total urine was collected for 24 h. Pooled 24 h urine samples were preserved with 10% thymol solution and frozen at 20 C until analyzed for % sugar excretion (Table 1). A previously validated alditol acetate derivatization was used and sugar was quantified using gas
85
chromatography with flame ionization detection. A mixed ANOVA was used to investigate the differences due to the fixed effects of diet and period. Differences were defined at P < 0.05. There was an effect of diet on % sugar excretion for all sugars, characterized by the HP group generally having a higher permeability. This indicates that diets with higher % of smaller feed particles may result in increased GIT permeability. Permeability following ulcer induction was lower than treatment or washout periods. This challenges the effective use of permeability, measured as % sugar excretion, in determining clinical ulceration. Key Words: particle size, permeability, oats
105 Digestibility of different diets after a weight gain protocol in Standardbreds, Andalusians, and mixed-breed ponies S.J. Potter 1, N.J. Bamford 1, P.A. Harris 2, S.R. Bailey*1 1 University of Melbourne, Melbourne, Victoria, Australia; 2 Waltham Centre for Pet Nutrition, Waltham on the Wolds, Leicestershire, United Kingdom Ponies and certain horse breeds tend to gain weight easily and are often called ‘easy keepers’. It is unknown whether these breed/type differences could be due to nutrient digestibility differences. This study assessed digestibility in 2 similar-sized horse breeds (one insulin sensitive and one relatively insulin resistant) and mixed-breed ponies after a 20wks weight gain protocol using different diets. Eight Standardbred horses (4e20yrs), 8 mixed-breed ponies (5e16yrs) and 8 Andalusian/ Andalusian-cross horses (3e13yr) with moderate initial BCS were evaluated. Over 2 study periods, 3 animals of each breed were fed for maintenance, (hay plus a ration balancer, oaten chaff and soybean hull pellets: control); 2 crossed to the weight-gain groups for the second period, and one of each breed crossed to the maintenance group after re-attaining moderate BCS. Four animals of each breed were fed the control diet plus a rising plane of nutrition up to 201% of maintenance energy requirements using either a high fat diet (HF: added fat/ oil increasing to 200g/100 kg BW: Lucerne chaff, canola oil plus granulated vegetable fat) or an isocaloric high grain diet (HG: HF diet with oil/fat replaced by micronized maize progressively increasing to 455g/100kg BW). After 20 wk, those on the weight gain diets had all significantly increased BCS to 7/9. Hay was available ad libitum except for the collection period when given 2.5% BW DM. Apparent digestibility of gross energy (GE), fat (CF) and protein (CP) as well as starch and neutral detergent fiber (NDF) digestibilities were determined, and fecal pH plus DM monitored, during a 24hr total fecal output collection at the end of the study. During the collection period, feed consumption corrected for BW was similar between the breeds. There was no effect of breed/diet on fecal pH or DM. There were no
Table 1 Percent sugar marker excretion for total 24-h urine collection Sugar marker
Sugar dose (mg/kg BW)
Percent excretion HA
Mannitol Sucralose Lactulose Sucrose
40 200 70 70
1.6 0.8 2.2 2.8
P-value HO
± ± ± ±
0.1a 0.4ab 0.5a 1.1ab
2.1 0.8 2.3 2.4
HOP ± ± ± ±
0.6b 0.3ab 0.7ab 0.7a
2.2 0.5 2.0 2.0
± ± ± ±
HP 0.5b 0.2a 0.6a 0.4a
2.6 1.1 2.9 3.4
± ± ± ±
0.5b 0.4b 0.5b 0.4b
<0.001 <0.05 <0.05 <0.05