- Email: [email protected]
Fecal and saliva IgA secretion when feeding a concentrated mannan oligosaccharide to neonatal dairy calves
The Professional Animal Scientist 29 (2013):457–462
©2013 American Registry of Professional Animal Scientists
Fecal and saliva IgA secretion when feeding a concentrated mannan oligosaccharide to neonatal dairy calves
A. J. Heinrichs,1 PAS, B. S. Heinrichs, and C. M. Jones Department of Animal Science, The Pennsylvania State University, University Park 16802
ABSTRACT The influence of supplementing milk replacer with a mannan-rich fraction (MRF) on adaptive immunity and growth of neonatal dairy calves was investigated using 2 groups of 30 heifer calves. In conjunction, the potential of measuring salivary and fecal IgA as an indicator of mucosal health was studied. Milk replacer was supplemented with 0 or 1 g/d of yeast-derived MRF (Actigen; Alltech Inc., Nicholasville, KY) and fed through weaning at 6 wk of age. Average daily gain tended to be greater for calves fed MRF (517 vs. 411 g/d; P < 0.07), but no effects were observed in measures of skeletal growth. Calves fed MRF in milk replacer had fewer days with high scour scores compared with control calves, and salivary and fecal IgA were elevated earlier in life for MRF-fed calves. No differences were observed in respiratory illness between treatments. In conclusion, salivary IgA was found to be an indicator of fecal IgA; however, it was not as sensitive a measurement of scours because it parallels what is happening in feces. In addition, MRF-fed calves had improved fecal scores compared with control calves
1
Corresponding author: [email protected]
in this study where all calves had some level of cryptosporidium infection that was a direct cause of scours. Key words: dairy calf, mannan oligosaccharide, prebiotic supplement, fecal IgA, salivary IgA
INTRODUCTION Supplementation of calf milk replacer with mannan oligosaccharide (MOS) has become relatively common in the United States and throughout the world, presumably in response to societal pressure to limit the use of antibiotics in animal production. Despite its commercial use in milk replacer, research over the past decade has found calf performance when feeding MOS has varied. In some reports, feeding MOS in milk replacer led to improved ADG and feed efficiency (Król, 2011; Ghosh and Mehla, 2012), whereas in other studies no growth effects were detected (Hill et al., 2008; da Silva et al., 2012). Likewise, in some experiments MOS has improved fecal consistency and reduced severity of diarrhea (Heinrichs et al., 2003; Morrison et al., 2010), but in others this effect has not been observed (Uzmay et al., 2011; da Silva et al., 2012). Many
gram-negative bacteria attach to the intestinal epithelium using mannosespecific fimbriae, and MOS has limited bacterial colonization of the gut in monogastric species by providing competitive binding sites (Spring et al., 2000). In a recent review of MOS mode of action in monogastric species, Halas and Nochta (2012) concluded that MOS can efficiently reduce the number of pathogens during an infection but results in a clean environment, and the effects of MOS on beneficial bacteria are inconsistent. Supplementation with MOS has been shown to increase intestinal mucous production in turkeys, aid recovery of damaged intestinal mucosal cells in piglets, and enhance gut maturation in broilers (Halas and Nochta, 2012). In addition, MOS has been found to improve both specific and nonspecific immune responses (Halas and Nochta, 2012). These functions are positive and appear promising in terms of using MOS to reduce diarrhea incidence and severity in the neonatal calf. Immunoglobulin A is the main element of the humoral response that provides protection against antigens at mucosal surfaces. As such, IgA is normally found in saliva and in small intestinal secretions (Newby and Bourne, 1976). It is important for
458
Heinrichs et al.
Table 1. Nutrient composition of milk replacer and calf starter fed to 30 Holstein calves1 Milk replacer Item DM (%) Moisture (%) CP (% DM) Soluble protein (% CP) Fat acid hydrolysis (% DM) ADF (% DM) NDF (% DM) Ash (% DM) Ca (% DM) P (% DM) Mg (% DM) K (% DM) Na (% DM) Fe (mg/kg) Mg (mg/kg) Zn (mg/kg) Cu (mg/kg) TDN (% DM) NEm (Mcal/kg) NEg (Mcal/kg) 1
Mean
SD
Calf starter
94.7 5.2 20.9 — 19.9 — — — 0.7 0.7 — — 0.9 — — — — — — —
0.6 0.6 0.5 — 0.3 — — — 0.1 0.0 — — 0.1 — — — — — — —
85.5 14.5 20.1 14.1 — 7.4 16.2 7.2 1.15 0.52 0.35 1.51 0.51 325 79 115 16 77.9 1.87 1.23
Milk replacer contained 0.05 g/kg of Deccox (Alpharma Inc., Bridgewater, NJ).
gut homeostasis and the interactions between B cells and bacterial flora in the gut. Secretory IgA is found in bovine colostrum, but this form of IgA is short lived and has a 2-d half-life (Porter, 1972). Typical IgA concentrations observed in colostrum range from 0.5 to 4.4 mg/mL with an average of 1.66 mg/mL, or approximately 3% of the total Ig found in bovine colostrum (Kehoe et al., 2007). This means that any maternal IgA derived from colostrum fed immediately after birth will be at very low levels in the blood of neonatal calves by 4 to 6 d of age. In total, IgA has been studied very little in the bovine neonate. Our objective was to study the influence of supplementing milk replacer with a mannan-rich fraction (MRF) on adaptive immunity and growth of neonatal dairy calves.
MATERIALS AND METHODS This study was approved by the Institutional Animal Care and Use Committee of the Pennsylvania
State University (IACUC #34829). Two groups of 30 heifer calves were randomly assigned to treatment at birth. Calves were fed colostrum for 2 feedings (1 d) and transition milk for 2 d before being changed to milk replacer. Colostrum was analyzed for IgG and IgA concentration using ELISA (Bethyl Laboratories Inc., Montgomery, TX). Immunoglobulin status at 24 h of age was estimated by measuring blood total protein with a refractometer to ensure that calves received adequate antibodies from colostrum by passive transfer. The control group was fed twice daily using a commercial milk replacer (20% protein, 20% fat; Milk Specialties Global, Eden Prairie, MN; Table 1). The treatment group was fed the same milk replacer supplemented with yeast-derived MRF mixed at 1 g/d (Actigen; Alltech Inc., Nicholasville, KY). Actigen is a second-generation, mannan-rich, bioactive fraction derived from the outer wall of a specific strain of yeast. Milk replacer was fed twice daily at 6% of BW per feeding,
and starter grain and water were provided ad libitum. During wk 5 of age, milk was fed at 6% of BW one time a day only; calves were weaned at 6 wk of age. Starter grain (Eastgate Feed Mill, Eastgate, PA; Table 1) was added daily, with uneaten grain collected weekly to monitor feed intake. There were no milk replacer refusals. Scores evaluating fecal matter, respiratory health, and overall general appearance were assigned daily to evaluate health performance between groups (Lesmeister et al., 2004). All diagnosed illnesses and treatments given were recorded. Body weight was measured at birth and growth parameters were measured weekly thereafter, including weight, hip height, withers height, and heart girth. Saliva samples were collected at d 2, 4, 6, 8, 10, 12, 14, 16, 18, and 20 using a small cotton ball placed inside the mouth of the calf until it was reasonably wet (1 to 2 min). The cotton with absorbed saliva was placed in a 10-mL syringe and compressed to recover liquid. Fecal samples were taken from the rectum on d 2, 4, 6, 8, 10, 12, 14, 16, 18, and 20. Saliva and fecal samples were analyzed for IgA content using ELISA (Bethyl Laboratories). Samples of grain and milk replacer were taken weekly. Respective samples were composited and stored at −20°C for standard feed analysis (Cumberland Valley Analytical Service, Hagerstown, MD). Data were analyzed using the Mixed procedure of SAS (Version 8, SAS Institute Inc., Cary, NC) allowing for repeated measures. Calves were considered random. Nonlinear time was accounted for with polynomial terms when needed. Treatment-bytime interactions up to the highest polynomial needed were considered but removed for reasons of parsimony when not significant. Adjusted means at specific times of interest were compared. After taking advantage of the longitudinal nature of the data in the statistical analysis, the more easily understood estimated concentrations and confidence bands were computed. Where confidence bands do not over-
IgA secretion and mannan oligosaccharide for dairy calves
Table 2. Immunoglobulin concentrations in colostrum and serum of calves at 24 h of age fed 0 or 1 g/d of a mannan-rich fraction1 (MRF) in milk replacer Item
Control
MRF
SEM
74.3 2.9 5.9 22.65
72.1 2.5 6.0 20.07
0.3 0.6 0.9 1.69
Colostrum IgG (mg/mL) Colostrum IgA (mg/mL) Total serum protein (g/dL) Serum IgG (mg/mL) 1
Actigen (Alltech Inc., Nicholasville, KY).
lap, differences are significant (P < 0.05).
RESULTS AND DISCUSSION Nutrient composition of milk replacer and calf starter used in this study is shown in Table 1. Actual feed composition matched planned diets, and these feedstuffs should have provided adequate nutrients for the calves. There was no mortality of calves on the study; however, 17 calves were
treated for respiratory illness (n = 8 for control; n = 9 for treatment; Naxel; Pfizer Inc., New York, NY) that was likely unrelated to the study objective. Overall respiratory scores were not different between the 2 treatment groups. At d 14 to 18 of age a fecal sample was taken from each calf and analyzed for the presence of cryptosporidium using the X/pect Cryptosporidium Diagnostic Kit (Remel Inc., Lenexa, KS). All calves were found to be shed-
Table 3. Least squares means of growth, feed intake, and fecal scores of calves fed 0 or 1 g/d of a mannan-rich fraction1 (MRF) in milk replacer and weaned at 6 wk of age Item BW (kg) Birth Weaning ADG (g/d) Hip height (cm) Birth Weaning Withers height (cm) Birth Weaning Heart girth (cm) Birth Weaning Intake (wk 1 to 5) Starter (kg/d) Milk (kg/d) Total DM (kg/d) Feed:Gain (wk 1 to 6) Fecal scour score
Control
42.4 56.8 411b 79.9 86.4 76.7 83.0 87.7 96.3 1.598 0.668 2.265 5.5c 1.43
MRF
40.6 58.7 517a 80.4 86.9 76.5 82.8 86.7 96.5 1.325 0.682 2.007 3.9d 1.35
SEM
Means in the same row with different letters are different at P < 0.07. Means in the same row with different letters are different at P < 0.05. 1 Actigen (Alltech Inc., Nicholasville, KY). a,b c,d
0.61 0.62 1.13 0.32 0.33 0.30 0.31 0.47 0.46 0.195 0.022 0.169 0.110 0.040
459
ding cryptosporidium during this time period and were given electrolytes (Bluelite; TechMix LLC, Stewart, MN) for 3 d. Because of the ongoing problems of cryptosporidium in the facility, 10 calves were treated for severe scours that also included elevated temperatures (>40°C; n = 5 for control; n = 5 for treatment; Nuflor; Intervet, Roseland, NJ). All calves recovered; however, feed efficiencies (g of feed/g of gain) were lower for the study as a result. Colostrum fed to the calves was analyzed for IgG and IgA concentration to ensure all calves received adequate colostrum quality to allow them to acquire adequate passive immunity. Blood total protein was adequate for all calves at 24 h of age (Table 2), indicating that calves had adequate passive transfer of immunoglobulin from colostrum. Body weights were similar between control and treatment groups at the start and end of the study (Table 3). Because control calves were slightly larger at the start and slightly smaller at the end, there was a trend (P < 0.07) for increased ADG in favor of the MRF-fed calves. There were no significant differences in any skeletal measurements. Withers height, hip width, and heart girth were the same for the 2 groups of calves (Table 3). Feed intake was similar for both groups, although numerically less grain was consumed by the MRF group. Feed-to-gain ratios were much higher than anticipated because of moderate bouts of scours from cryptosporidium. The MRF group was more efficient than the control group because of differences in ADG and starter intake (P < 0.05). This fits well with the decreased scours, which will be discussed later. Growth effects have not been observed in most previous studies with MOS (Hill et al., 2008; Morrison et al., 2010; da Silva et al., 2012), and in 2 studies where calf growth was enhanced, starter intake was also improved in MOS-fed calves (Król, 2011; Ghosh and Mehla, 2012). In another experiment, starter intake was increased before weaning but did not lead to differences in
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Heinrichs et al.
Figure 1. Salivary IgA concentration in calves fed 0 (solid lines) or 1 (dashed lines) g/d of a mannan-rich fraction (MRF) in milk replacer. For each treatment, bold lines indicate the expected mean with 95% confidence limits in gray.
Table 4. Salivary and fecal IgA of calves fed 0 or 1 g/d of a mannan-rich fraction1 (MRF) in milk replacer and weaned at 6 wk of age Control Item Salivary IgA (μg/mL) d2 d4 d6 d8 d 10 d 12 d 14 d 16 d 18 d 20 Fecal IgA (μg/mL) d2 d4 d6 d8 d 10 d 12 d 14 d 16 d 18 d 20
0.05 0.04 0.05 0.04 0.06 0.07 0.24 0.14 0.13b 0.20b 1.96 1.27 0.52 0.53 0.54 0.94 0.85 0.65b 0.62b 0.38b
SD
0.04 0.03 0.03 0.02 0.05 0.08 0.26 0.14 0.14 0.20 2.75 1.76 0.32 0.35 0.51 0.86 0.67 0.47 0.49 0.29
Means with different superscripts differ at P < 0.05. Actigen (Alltech Inc., Nicholasville, KY).
a,b 1
Mean
MRF Mean
0.10 0.04 0.08 0.05 0.09 0.11 0.33 0.15 0.27a 0.55a 1.09 1.59 0.51 0.52 0.86 1.62 1.09 3.08a 1.88a 1.30a
SD
0.15 0.04 0.24 0.05 0.15 0.14 0.50 0.26 0.45 0.90 1.28 2.29 0.59 0.37 0.69 1.99 1.11 4.74 2.91 1.95
growth between control and MOS-fed calves (Terré et al., 2007). Mean salivary IgA concentrations are shown in Table 4, and Figure 1 presents estimated concentrations with confidence bands. The computed data (Figure 1) shows treatment differences while taking into account the longitudinal nature through repeated measurements of all the data from the study. Where the confidence bands do not overlap, the differences are significant (P < 0.05). These results show a small amount of residual IgA obtained from colostrum; however, this decreased by 4 to 6 d of age. By 12 to 14 d of age, salivary IgA concentrations were increasing in both groups and were greater in the MRF-fed calves than in the control calves. At 16 d of age the MRF-fed calves had significantly greater IgA levels than did control calves, and it remained that way for the period of time where measurements were taken. Figure 2 shows similar data and analysis for fecal IgA, and greater concentrations of IgA in feces compared with saliva are readily apparent. Fecal IgA is a more direct measure of IgA secreted by the intestinal mucosa, and it should be noted that the trends observed for salivary IgA are similar to those for fecal IgA. Intestinally secreted IgA is a more direct measure of intestinal immunity, because this IgA is available to respond to a challenge and affect the organisms that are inducing scours in the calf. Similar to the results for salivary IgA, fecal IgA concentrations indicate some residual colostral IgA in the first 4 to 6 d of life. Fecal IgA increased at 8 to 10 d, earlier than observed in saliva. Similar to saliva, MRF-fed calves had greater (P < 0.05) fecal IgA concentrations compared with the control calves by 13 d of age, and this difference remained throughout the period of measurement. The increased IgA secretion in MRF-fed calves was likely a contributing factor in the lower scours score (P < 0.05) for MRF calves in this study. Figure 3 shows the summary of scour scores based on using
461
IgA secretion and mannan oligosaccharide for dairy calves
56 d of age. In contrast, Terré et al. (2007) saw no effect of MOS on fecal scores or fecal coliform counts, but did observe that MOS-fed calves had lower fecal cryptosporidia counts in the first week of life.
IMPLICATIONS
Figure 2. Fecal IgA concentration in calves fed 0 (solid lines) or 1 (dashed lines) g/d of a mannan-rich fraction (MRF) in milk replacer. For each treatment, bold lines indicate the expected mean with 95% confidence limits in gray.
all of the data over time, with confidence bands. The MRF-fed calves had lower scours from 9 through 20 d of age (P < 0.05). This corresponds well with the time period where fecal and salivary IgA concentrations were increased by feeding MRF. Other studies have observed improved fecal
scores in calves fed MOS (Heinrichs et al., 2003; Morrison et al., 2010). Ghosh and Mehla (2012) found that MOS improved fecal score and lowered the number of coliforms in feces, and Król (2011) found that calves fed MOS had improved fecal scores and greater serum IgG concentrations at
Neonatal calves had improved intestinal health compared with control calves in this study when calves were fed a mannan-rich, bioactive fraction derived from the outer wall of yeast. Salivary and fecal IgA were beneficially elevated earlier in life for the MRF-fed calves. In addition, salivary IgA was found to be an indicator of fecal IgA; however, it was not as sensitive a measurement of scours because it parallels what is happening in feces. It may offer a method of collecting and analyzing mucosal IgA production by calves that is easier to use in some studies.
ACKNOWLEDGMENTS This research is a component of NC-1042, Management Systems to Improve the Economic and Environmental Sustainability of Dairy Enterprises. The authors acknowledge and thank Alltech Inc., Nicholasville, Kentucky, for donation of products used in this study as well as partial support for wages.
LITERATURE CITED da Silva, J. T., C. M. M. Bittar, and L. S. Ferreira. 2012. Evaluation of mannan-oligosaccharides offered in milk replacers or calf starters and their effect on performance and rumen development of dairy calves. R. Bras. Zootec. 41:746–752. Ghosh, S., and R. K. Mehla. 2012. Influence of dietary supplementation of prebiotics (mannanoligosaccharide) on the performance of crossbred calves. Trop. Anim. Health Prod. 44:617–622. Halas, V., and I. Nochta. 2012. Mannan oligosaccharides in nursery pig nutrition and their potential mode of action. Animals 2:261–274.
Figure 3. Fecal score (5-point scale, 1 = normal) of calves fed 0 (solid lines) or 1 (dashed lines) g/d of a mannan-rich fraction (MRF) in milk replacer. For each treatment, bold lines indicate the expected mean with 95% confidence limits in gray.
Heinrichs, A. J., C. M. Jones, and B. S. Heinrichs. 2003. Effects of mannan oligosaccharide or antibiotics in neonatal diets on
462 health and growth of dairy calves. J. Dairy Sci. 86:4064–4069. Hill, T. M., H. G. Bateman II, J. M. Aldrich, and R. L. Schlotterbeck. 2008. Oligosaccharides for dairy calves. Prof. Anim. Sci. 24:460–464. Kehoe, S. I., B. M. Jayarao, and A. J. Heinrichs. 2007. A survey of bovine colostrum composition and colostrum management on Pennsylvania dairy farms. J. Dairy Sci. 90:4108–4116. Król, B. 2011. Effect of mannanoligosaccharides, inulin and yeast nucleotides added to calf milk replacers on rumen microflora, level of serum immunoglobulin and health condition of calves. Electronic J. Polish Agric. Univ. 14:Article 18. Lesmeister, K. E., A. J. Heinrichs, and M. T. Gabler. 2004. Effects of supplemental yeast
Heinrichs et al. (Saccharomyces cerevisiae) culture on rumen development, growth characteristics, and blood parameters in neonatal dairy calves. J. Dairy Sci. 87:1832–1839. Morrison, S. J., S. Dawson, and A. F. Carson. 2010. The effects of mannan oligosaccharide and Streptococcus faecium addition to milk replacer on calf health and performance. Livest. Sci. 131:292–296. Newby, T. J., and F. J. Bourne. 1976. The nature of local immune systems of the bovine small intestine. Immunology 31:475–480. Porter, P. 1972. Immunoglobulins in bovine mammary secretions: Quantitative changes in early lactation and absorption by the neonatal calf. Immunology 23:225–238. Spring, P., C. Wenk, K. A. Dawson, and K. E. Newman. 2000. The effects of dietary mannanoligosaccharides on cecal parameters and
the concentrations of enteric bacteria in the ceca of Salmonella-challenged broiler chicks. Poult. Sci. 79:205–211. Terré, M., M. A. Calvo, C. Adelantado, A. Kocher, and A. Bach. 2007. Effects of mannan oligosaccharides on performance and microorganism fecal counts of calves following an enhanced-growth feeding program. Anim. Feed Sci. Technol. 137:115–125. Uzmay, C., A. Kiliç, I. Kaya, H. Özkul, S. S. Önenç, and M. Polat. 2011. Effect of mannan oligosaccharide addition to whole milk on growth and health of Holstein calves. Arch. Tierzucht 54:127–136.
©2013 American Registry of Professional Animal Scientists
Fecal and saliva IgA secretion when feeding a concentrated mannan oligosaccharide to neonatal dairy calves
A. J. Heinrichs,1 PAS, B. S. Heinrichs, and C. M. Jones Department of Animal Science, The Pennsylvania State University, University Park 16802
ABSTRACT The influence of supplementing milk replacer with a mannan-rich fraction (MRF) on adaptive immunity and growth of neonatal dairy calves was investigated using 2 groups of 30 heifer calves. In conjunction, the potential of measuring salivary and fecal IgA as an indicator of mucosal health was studied. Milk replacer was supplemented with 0 or 1 g/d of yeast-derived MRF (Actigen; Alltech Inc., Nicholasville, KY) and fed through weaning at 6 wk of age. Average daily gain tended to be greater for calves fed MRF (517 vs. 411 g/d; P < 0.07), but no effects were observed in measures of skeletal growth. Calves fed MRF in milk replacer had fewer days with high scour scores compared with control calves, and salivary and fecal IgA were elevated earlier in life for MRF-fed calves. No differences were observed in respiratory illness between treatments. In conclusion, salivary IgA was found to be an indicator of fecal IgA; however, it was not as sensitive a measurement of scours because it parallels what is happening in feces. In addition, MRF-fed calves had improved fecal scores compared with control calves
1
Corresponding author: [email protected]
in this study where all calves had some level of cryptosporidium infection that was a direct cause of scours. Key words: dairy calf, mannan oligosaccharide, prebiotic supplement, fecal IgA, salivary IgA
INTRODUCTION Supplementation of calf milk replacer with mannan oligosaccharide (MOS) has become relatively common in the United States and throughout the world, presumably in response to societal pressure to limit the use of antibiotics in animal production. Despite its commercial use in milk replacer, research over the past decade has found calf performance when feeding MOS has varied. In some reports, feeding MOS in milk replacer led to improved ADG and feed efficiency (Król, 2011; Ghosh and Mehla, 2012), whereas in other studies no growth effects were detected (Hill et al., 2008; da Silva et al., 2012). Likewise, in some experiments MOS has improved fecal consistency and reduced severity of diarrhea (Heinrichs et al., 2003; Morrison et al., 2010), but in others this effect has not been observed (Uzmay et al., 2011; da Silva et al., 2012). Many
gram-negative bacteria attach to the intestinal epithelium using mannosespecific fimbriae, and MOS has limited bacterial colonization of the gut in monogastric species by providing competitive binding sites (Spring et al., 2000). In a recent review of MOS mode of action in monogastric species, Halas and Nochta (2012) concluded that MOS can efficiently reduce the number of pathogens during an infection but results in a clean environment, and the effects of MOS on beneficial bacteria are inconsistent. Supplementation with MOS has been shown to increase intestinal mucous production in turkeys, aid recovery of damaged intestinal mucosal cells in piglets, and enhance gut maturation in broilers (Halas and Nochta, 2012). In addition, MOS has been found to improve both specific and nonspecific immune responses (Halas and Nochta, 2012). These functions are positive and appear promising in terms of using MOS to reduce diarrhea incidence and severity in the neonatal calf. Immunoglobulin A is the main element of the humoral response that provides protection against antigens at mucosal surfaces. As such, IgA is normally found in saliva and in small intestinal secretions (Newby and Bourne, 1976). It is important for
458
Heinrichs et al.
Table 1. Nutrient composition of milk replacer and calf starter fed to 30 Holstein calves1 Milk replacer Item DM (%) Moisture (%) CP (% DM) Soluble protein (% CP) Fat acid hydrolysis (% DM) ADF (% DM) NDF (% DM) Ash (% DM) Ca (% DM) P (% DM) Mg (% DM) K (% DM) Na (% DM) Fe (mg/kg) Mg (mg/kg) Zn (mg/kg) Cu (mg/kg) TDN (% DM) NEm (Mcal/kg) NEg (Mcal/kg) 1
Mean
SD
Calf starter
94.7 5.2 20.9 — 19.9 — — — 0.7 0.7 — — 0.9 — — — — — — —
0.6 0.6 0.5 — 0.3 — — — 0.1 0.0 — — 0.1 — — — — — — —
85.5 14.5 20.1 14.1 — 7.4 16.2 7.2 1.15 0.52 0.35 1.51 0.51 325 79 115 16 77.9 1.87 1.23
Milk replacer contained 0.05 g/kg of Deccox (Alpharma Inc., Bridgewater, NJ).
gut homeostasis and the interactions between B cells and bacterial flora in the gut. Secretory IgA is found in bovine colostrum, but this form of IgA is short lived and has a 2-d half-life (Porter, 1972). Typical IgA concentrations observed in colostrum range from 0.5 to 4.4 mg/mL with an average of 1.66 mg/mL, or approximately 3% of the total Ig found in bovine colostrum (Kehoe et al., 2007). This means that any maternal IgA derived from colostrum fed immediately after birth will be at very low levels in the blood of neonatal calves by 4 to 6 d of age. In total, IgA has been studied very little in the bovine neonate. Our objective was to study the influence of supplementing milk replacer with a mannan-rich fraction (MRF) on adaptive immunity and growth of neonatal dairy calves.
MATERIALS AND METHODS This study was approved by the Institutional Animal Care and Use Committee of the Pennsylvania
State University (IACUC #34829). Two groups of 30 heifer calves were randomly assigned to treatment at birth. Calves were fed colostrum for 2 feedings (1 d) and transition milk for 2 d before being changed to milk replacer. Colostrum was analyzed for IgG and IgA concentration using ELISA (Bethyl Laboratories Inc., Montgomery, TX). Immunoglobulin status at 24 h of age was estimated by measuring blood total protein with a refractometer to ensure that calves received adequate antibodies from colostrum by passive transfer. The control group was fed twice daily using a commercial milk replacer (20% protein, 20% fat; Milk Specialties Global, Eden Prairie, MN; Table 1). The treatment group was fed the same milk replacer supplemented with yeast-derived MRF mixed at 1 g/d (Actigen; Alltech Inc., Nicholasville, KY). Actigen is a second-generation, mannan-rich, bioactive fraction derived from the outer wall of a specific strain of yeast. Milk replacer was fed twice daily at 6% of BW per feeding,
and starter grain and water were provided ad libitum. During wk 5 of age, milk was fed at 6% of BW one time a day only; calves were weaned at 6 wk of age. Starter grain (Eastgate Feed Mill, Eastgate, PA; Table 1) was added daily, with uneaten grain collected weekly to monitor feed intake. There were no milk replacer refusals. Scores evaluating fecal matter, respiratory health, and overall general appearance were assigned daily to evaluate health performance between groups (Lesmeister et al., 2004). All diagnosed illnesses and treatments given were recorded. Body weight was measured at birth and growth parameters were measured weekly thereafter, including weight, hip height, withers height, and heart girth. Saliva samples were collected at d 2, 4, 6, 8, 10, 12, 14, 16, 18, and 20 using a small cotton ball placed inside the mouth of the calf until it was reasonably wet (1 to 2 min). The cotton with absorbed saliva was placed in a 10-mL syringe and compressed to recover liquid. Fecal samples were taken from the rectum on d 2, 4, 6, 8, 10, 12, 14, 16, 18, and 20. Saliva and fecal samples were analyzed for IgA content using ELISA (Bethyl Laboratories). Samples of grain and milk replacer were taken weekly. Respective samples were composited and stored at −20°C for standard feed analysis (Cumberland Valley Analytical Service, Hagerstown, MD). Data were analyzed using the Mixed procedure of SAS (Version 8, SAS Institute Inc., Cary, NC) allowing for repeated measures. Calves were considered random. Nonlinear time was accounted for with polynomial terms when needed. Treatment-bytime interactions up to the highest polynomial needed were considered but removed for reasons of parsimony when not significant. Adjusted means at specific times of interest were compared. After taking advantage of the longitudinal nature of the data in the statistical analysis, the more easily understood estimated concentrations and confidence bands were computed. Where confidence bands do not over-
IgA secretion and mannan oligosaccharide for dairy calves
Table 2. Immunoglobulin concentrations in colostrum and serum of calves at 24 h of age fed 0 or 1 g/d of a mannan-rich fraction1 (MRF) in milk replacer Item
Control
MRF
SEM
74.3 2.9 5.9 22.65
72.1 2.5 6.0 20.07
0.3 0.6 0.9 1.69
Colostrum IgG (mg/mL) Colostrum IgA (mg/mL) Total serum protein (g/dL) Serum IgG (mg/mL) 1
Actigen (Alltech Inc., Nicholasville, KY).
lap, differences are significant (P < 0.05).
RESULTS AND DISCUSSION Nutrient composition of milk replacer and calf starter used in this study is shown in Table 1. Actual feed composition matched planned diets, and these feedstuffs should have provided adequate nutrients for the calves. There was no mortality of calves on the study; however, 17 calves were
treated for respiratory illness (n = 8 for control; n = 9 for treatment; Naxel; Pfizer Inc., New York, NY) that was likely unrelated to the study objective. Overall respiratory scores were not different between the 2 treatment groups. At d 14 to 18 of age a fecal sample was taken from each calf and analyzed for the presence of cryptosporidium using the X/pect Cryptosporidium Diagnostic Kit (Remel Inc., Lenexa, KS). All calves were found to be shed-
Table 3. Least squares means of growth, feed intake, and fecal scores of calves fed 0 or 1 g/d of a mannan-rich fraction1 (MRF) in milk replacer and weaned at 6 wk of age Item BW (kg) Birth Weaning ADG (g/d) Hip height (cm) Birth Weaning Withers height (cm) Birth Weaning Heart girth (cm) Birth Weaning Intake (wk 1 to 5) Starter (kg/d) Milk (kg/d) Total DM (kg/d) Feed:Gain (wk 1 to 6) Fecal scour score
Control
42.4 56.8 411b 79.9 86.4 76.7 83.0 87.7 96.3 1.598 0.668 2.265 5.5c 1.43
MRF
40.6 58.7 517a 80.4 86.9 76.5 82.8 86.7 96.5 1.325 0.682 2.007 3.9d 1.35
SEM
Means in the same row with different letters are different at P < 0.07. Means in the same row with different letters are different at P < 0.05. 1 Actigen (Alltech Inc., Nicholasville, KY). a,b c,d
0.61 0.62 1.13 0.32 0.33 0.30 0.31 0.47 0.46 0.195 0.022 0.169 0.110 0.040
459
ding cryptosporidium during this time period and were given electrolytes (Bluelite; TechMix LLC, Stewart, MN) for 3 d. Because of the ongoing problems of cryptosporidium in the facility, 10 calves were treated for severe scours that also included elevated temperatures (>40°C; n = 5 for control; n = 5 for treatment; Nuflor; Intervet, Roseland, NJ). All calves recovered; however, feed efficiencies (g of feed/g of gain) were lower for the study as a result. Colostrum fed to the calves was analyzed for IgG and IgA concentration to ensure all calves received adequate colostrum quality to allow them to acquire adequate passive immunity. Blood total protein was adequate for all calves at 24 h of age (Table 2), indicating that calves had adequate passive transfer of immunoglobulin from colostrum. Body weights were similar between control and treatment groups at the start and end of the study (Table 3). Because control calves were slightly larger at the start and slightly smaller at the end, there was a trend (P < 0.07) for increased ADG in favor of the MRF-fed calves. There were no significant differences in any skeletal measurements. Withers height, hip width, and heart girth were the same for the 2 groups of calves (Table 3). Feed intake was similar for both groups, although numerically less grain was consumed by the MRF group. Feed-to-gain ratios were much higher than anticipated because of moderate bouts of scours from cryptosporidium. The MRF group was more efficient than the control group because of differences in ADG and starter intake (P < 0.05). This fits well with the decreased scours, which will be discussed later. Growth effects have not been observed in most previous studies with MOS (Hill et al., 2008; Morrison et al., 2010; da Silva et al., 2012), and in 2 studies where calf growth was enhanced, starter intake was also improved in MOS-fed calves (Król, 2011; Ghosh and Mehla, 2012). In another experiment, starter intake was increased before weaning but did not lead to differences in
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Figure 1. Salivary IgA concentration in calves fed 0 (solid lines) or 1 (dashed lines) g/d of a mannan-rich fraction (MRF) in milk replacer. For each treatment, bold lines indicate the expected mean with 95% confidence limits in gray.
Table 4. Salivary and fecal IgA of calves fed 0 or 1 g/d of a mannan-rich fraction1 (MRF) in milk replacer and weaned at 6 wk of age Control Item Salivary IgA (μg/mL) d2 d4 d6 d8 d 10 d 12 d 14 d 16 d 18 d 20 Fecal IgA (μg/mL) d2 d4 d6 d8 d 10 d 12 d 14 d 16 d 18 d 20
0.05 0.04 0.05 0.04 0.06 0.07 0.24 0.14 0.13b 0.20b 1.96 1.27 0.52 0.53 0.54 0.94 0.85 0.65b 0.62b 0.38b
SD
0.04 0.03 0.03 0.02 0.05 0.08 0.26 0.14 0.14 0.20 2.75 1.76 0.32 0.35 0.51 0.86 0.67 0.47 0.49 0.29
Means with different superscripts differ at P < 0.05. Actigen (Alltech Inc., Nicholasville, KY).
a,b 1
Mean
MRF Mean
0.10 0.04 0.08 0.05 0.09 0.11 0.33 0.15 0.27a 0.55a 1.09 1.59 0.51 0.52 0.86 1.62 1.09 3.08a 1.88a 1.30a
SD
0.15 0.04 0.24 0.05 0.15 0.14 0.50 0.26 0.45 0.90 1.28 2.29 0.59 0.37 0.69 1.99 1.11 4.74 2.91 1.95
growth between control and MOS-fed calves (Terré et al., 2007). Mean salivary IgA concentrations are shown in Table 4, and Figure 1 presents estimated concentrations with confidence bands. The computed data (Figure 1) shows treatment differences while taking into account the longitudinal nature through repeated measurements of all the data from the study. Where the confidence bands do not overlap, the differences are significant (P < 0.05). These results show a small amount of residual IgA obtained from colostrum; however, this decreased by 4 to 6 d of age. By 12 to 14 d of age, salivary IgA concentrations were increasing in both groups and were greater in the MRF-fed calves than in the control calves. At 16 d of age the MRF-fed calves had significantly greater IgA levels than did control calves, and it remained that way for the period of time where measurements were taken. Figure 2 shows similar data and analysis for fecal IgA, and greater concentrations of IgA in feces compared with saliva are readily apparent. Fecal IgA is a more direct measure of IgA secreted by the intestinal mucosa, and it should be noted that the trends observed for salivary IgA are similar to those for fecal IgA. Intestinally secreted IgA is a more direct measure of intestinal immunity, because this IgA is available to respond to a challenge and affect the organisms that are inducing scours in the calf. Similar to the results for salivary IgA, fecal IgA concentrations indicate some residual colostral IgA in the first 4 to 6 d of life. Fecal IgA increased at 8 to 10 d, earlier than observed in saliva. Similar to saliva, MRF-fed calves had greater (P < 0.05) fecal IgA concentrations compared with the control calves by 13 d of age, and this difference remained throughout the period of measurement. The increased IgA secretion in MRF-fed calves was likely a contributing factor in the lower scours score (P < 0.05) for MRF calves in this study. Figure 3 shows the summary of scour scores based on using
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56 d of age. In contrast, Terré et al. (2007) saw no effect of MOS on fecal scores or fecal coliform counts, but did observe that MOS-fed calves had lower fecal cryptosporidia counts in the first week of life.
IMPLICATIONS
Figure 2. Fecal IgA concentration in calves fed 0 (solid lines) or 1 (dashed lines) g/d of a mannan-rich fraction (MRF) in milk replacer. For each treatment, bold lines indicate the expected mean with 95% confidence limits in gray.
all of the data over time, with confidence bands. The MRF-fed calves had lower scours from 9 through 20 d of age (P < 0.05). This corresponds well with the time period where fecal and salivary IgA concentrations were increased by feeding MRF. Other studies have observed improved fecal
scores in calves fed MOS (Heinrichs et al., 2003; Morrison et al., 2010). Ghosh and Mehla (2012) found that MOS improved fecal score and lowered the number of coliforms in feces, and Król (2011) found that calves fed MOS had improved fecal scores and greater serum IgG concentrations at
Neonatal calves had improved intestinal health compared with control calves in this study when calves were fed a mannan-rich, bioactive fraction derived from the outer wall of yeast. Salivary and fecal IgA were beneficially elevated earlier in life for the MRF-fed calves. In addition, salivary IgA was found to be an indicator of fecal IgA; however, it was not as sensitive a measurement of scours because it parallels what is happening in feces. It may offer a method of collecting and analyzing mucosal IgA production by calves that is easier to use in some studies.
ACKNOWLEDGMENTS This research is a component of NC-1042, Management Systems to Improve the Economic and Environmental Sustainability of Dairy Enterprises. The authors acknowledge and thank Alltech Inc., Nicholasville, Kentucky, for donation of products used in this study as well as partial support for wages.
LITERATURE CITED da Silva, J. T., C. M. M. Bittar, and L. S. Ferreira. 2012. Evaluation of mannan-oligosaccharides offered in milk replacers or calf starters and their effect on performance and rumen development of dairy calves. R. Bras. Zootec. 41:746–752. Ghosh, S., and R. K. Mehla. 2012. Influence of dietary supplementation of prebiotics (mannanoligosaccharide) on the performance of crossbred calves. Trop. Anim. Health Prod. 44:617–622. Halas, V., and I. Nochta. 2012. Mannan oligosaccharides in nursery pig nutrition and their potential mode of action. Animals 2:261–274.
Figure 3. Fecal score (5-point scale, 1 = normal) of calves fed 0 (solid lines) or 1 (dashed lines) g/d of a mannan-rich fraction (MRF) in milk replacer. For each treatment, bold lines indicate the expected mean with 95% confidence limits in gray.
Heinrichs, A. J., C. M. Jones, and B. S. Heinrichs. 2003. Effects of mannan oligosaccharide or antibiotics in neonatal diets on
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the concentrations of enteric bacteria in the ceca of Salmonella-challenged broiler chicks. Poult. Sci. 79:205–211. Terré, M., M. A. Calvo, C. Adelantado, A. Kocher, and A. Bach. 2007. Effects of mannan oligosaccharides on performance and microorganism fecal counts of calves following an enhanced-growth feeding program. Anim. Feed Sci. Technol. 137:115–125. Uzmay, C., A. Kiliç, I. Kaya, H. Özkul, S. S. Önenç, and M. Polat. 2011. Effect of mannan oligosaccharide addition to whole milk on growth and health of Holstein calves. Arch. Tierzucht 54:127–136.