Nutrition: Does adding MOS to sow diets help reproductive performance?

Monday, April 5, 2010

The answer is yes, according to research conducted at the University of Kentucky. And the piglets performed better from the jumpstart in weight that they received

by JANICE MURPHY

Mannan-oligosaccharides (MOS) are complex sugars commonly used in animal feed to encourage gastrointestinal health and performance. They are usually obtained from the yeast cell walls of Saccharomyces cerevisiae.

The mannan performs a specific function in the attachment of pathogenic bacteria, such as E. coli and salmonella. When bacteria recognize the mannan on intestinal cells, they bind to the cells and colonize the intestine, inevitably resulting in disease. However, when this recognition and attachment occurs with the mannan component of dietary MOS, those bacteria are never given the chance to bind to the intestinal wall and are instead flushed out of the system.

An experiment at the University of Kentucky recently focused on the effect of supplying MOS in sow diets on reproductive performance, milk composition and, subsequently, on the growth performance of their piglets, which were also fed with or without MOS in the nursery phase.

A total of 24 Yorkshire or Landrace × Yorkshire sows were allocated to two dietary treatments – a control diet that met National Research Council (NRC)) nutrient requirements or the control diet with a MOS product included at 0.2 per cent for both gestation and lactation diets.

The diets were corn-soybean meal based, providing 3,364 kilocalories per kg metabolizable energy (ME), 12.62  per cent protein, and 0.58 per cent lysine in gestation and 3,408 kcal/kg ME, 17.65  per cent protein and 1.01 per cent lysine in lactation.

Sows were individually floor fed 1.8 kg per day throughout gestation, starting 14 days before the expected farrowing date, or around day 102 of gestation. On day 108 of gestation, sows were moved to the farrowing facility, switched over to the lactation diet at a rate of 1.8 kg/d until farrowing and then fed ad libitum thereafter.

A total of 104 weaned piglets, representing seven litters of each sow treatment, were assigned to two diets – a control diet that met NRC nutrient requirements or the control diet with a MOS product included at 0.2 per cent for both phase one and phase two diets. The diets were corn-soybean meal based, providing 3,404 kcal/kg ME, 21.92  per cent protein and 1.38 per cent lysine in phase one (weeks 1 and 2); and 3,316 kcal/kg ME, 20.8 per cent protein and 1.21 per cent lysine in phase two (weeks 3 and 4). This created a two-by-two factorial arrangement with four experimental treatments overall –  control sow diet with control nursery diet, control sow diet with MOS nursery diet, MOS sow diet with control nursery diet, and MOS sow diet with MOS nursery diet.

The results revealed that feed intake during lactation increased slightly, although not significantly, by feeding MOS in the diet. However, sows fed MOS lost weight during lactation compared to sows fed the control diet (-7.69 versus 0.54 kg), a significant difference.

Litter weight at birth was not significantly different between MOS-fed and control sows.

This was not surprising considering that the experimental diets were introduced on day 102 of gestation. But both the litter weight at birth and weaning of sows fed MOS was numerically higher than sows fed the control diet. Expressed on an individual pig basis, sows fed MOS had heavier piglets than control sows for total pigs born, pigs born alive, and at weaning, the latter representing the only significant difference in average piglet weight. An increase in birth weight of 180 grams in the live-born pigs translated into 780 grams at weaning and 1,260 grams by the end of the nursery phase.

This increase in piglet body weights could be attributed to a number of factors, including increased sow milk production, increased nutrient content of the milk and/or increased metabolic efficiency of the piglets. The researchers suggested that the most likely explanation was an increase in milk production or nutrient concentration in the sow milk.

Although there was no attempt to measure milk production in this experiment, milk samples were collected and analyzed for protein, fat and lactose. The results showed no significant differences in milk components between treatments. However, there was a tendency for a lower lactose level during early lactation in MOS-fed sows.

The components that would most likely result in increased weight gain in piglets would be fat and protein. While these values were numerically higher in MOS-fed sow milk compared to control sow milk in both early lactation and late lactation, the difference was not statistically significant.

The immunoglobulin results mirrored the milk composition results. MOS treatment resulted in an increase of 10 per cent in immunoglobulin level in colostrum, but this was not statistically significant. Although immunoglobulin levels in colostrum and early or late lactation milk were numerically higher in MOS treatments (some more than 10 per cent), none yielded statistically significant differences.

The researchers are confident that there was a consistent increase in immunoglobulins but, because of the variability inherent in this type of measurement, the response would have had to be much larger to achieve statistical significance.

Growth performance of the nursery pigs is presented in Table 1. Piglets from sows fed MOS were significantly heavier than those from control sows, not only at weaning, but also at each weekly weigh-in for the entire nursery period.

Average daily gain (ADG), whether measured weekly or for each phase, was numerically higher for piglets from  MOS-fed sows than piglets from control sows. Overall, the ADG of piglets from MOS-fed sows was significantly higher compared to piglets from control sows (444 versus 405 grams). There was, however, no significant difference between sow treatments in the nursery feed intake or feed efficiency.

Based on the results, the researchers concluded that the inclusion of MOS in diets for sows in this study demonstrated clear improvements in reproductive performance, yielding heavier pigs at all time points. There was, however, no direct effect of MOS inclusion in the nursery diets on the piglets themselves.

When all was said and done, piglets from MOS-fed sows performed better as a result of the jumpstart in body weight they achieved prior to weaning, which they were able to carry through into the nursery and beyond. BP

Janice Murphy is a former Ontario agriculture ministry swine nutritionist who now lives and works in Prince Edward Island.

Source: I-fen Hung and Merlin D. Lindemann. 2009. Benefits of Mannan Oligosaccharides (MOS) for Sows and Weanling Pigs. Midwest Swine Nutrition Conference Proceedings, Indianapolis, Ind., Sept. 10, 2009. pp.46-55.