Researchers identified no issues with the inclusion of citrus pulp in the concentrated feed given to horses at a ratio of up to 28 percent.
Citrus pulp is a by-product of the orange juice industry. It is readily available and economically viable for inclusion in horse feed.
The researchers from Brazil and the United States conducted the study involving five adult horses in response to the increasing use of citrus pulp in horse feed.
The scientists from the University of Sao Paulo and Middle Tennessee State University set about evaluating citrus pulp use by investigating its nutrient digestibility and the diet carbohydrate fractions.
The horses used in the study were housed in individual stalls and fed diets formulated to meet the animals’ requirements for maintenance, with a roughage-to-concentrate ratio of 60:40. The roughage was fed as hay.
The formulated concentrates contained increasing levels of citrus pulp: 0%, 7%, 14%, 21%, and 28%.
There was no leftover food in the study, suggesting that the concentrate was well accepted by the animals.
To assess the feeds’ effectivemess, bedding was removed from the stalls during the study and the dung collected for analysis.
No effect of the diets was observed on the coefficients of digestibility of dry matter, organic matter, crude protein, ether extract, nitrogen-free extract, and non-fibrous carbohydrates. However, they did observe an effect on the soluble carbohydrates.
Roberta Brandi and her colleagues, whose findings were published int he journal Food and Nutrition Sciences, found that citrus pulp may be used in horse diets at up to 28% concentrate.
They described it was a safe energy source that benefited the digestibility of the nutrients and the carbohydrate fraction – both fibrous and non-fibrous – of the diet.
The researchers said carbohydrates were the main source of energy for horses, and they may be grouped into fibrous carbohydrates and non-fibrous carbohydrates.
The inclusion of easy fermentable carbohydrates reduced the level of starch in the diet without compromising the caloric density of the feed, they said.
They said the inclusion of citrus pulp or other sources of easily-fermentable fibers, such as beet pulp and soybean hulls, in horse diets was a trend in contemporary nutrition, as it allowed for a reduction in the supply of starch and a decrease in the magnitude of the glycemic and insulinemic curves. In doing so, they provided similar amounts of energy in a safe manner.
Most of the scientists involved in the research were involved in an earlier study that looked at the palatability of horse diets containing citrus pulp.
Concentrated feeds containing increasing levels of citrus pulp – 7%, 14%, 21% and 28% – were given to 10 healthy mares as part of their balanced daily diet.
The concentrate with 7% of citrus pulp presented the highest intake ratio, which the researchers assessed as the most preferred.
“Therefore, low levels of inclusion in the concentrate, close to 7%, are recommended when the concentrate is based on corn, wheat bran, soybean meal, with no flavour agents like molasses,” they said.
Brandi, R.A., Tribucci, A.M.O., Balieiro, J.C.C., Hoffman, R.M. and Bueno, I.C.S. (2014) Citrus Pulp in
Concentrates for Horses. Food and Nutrition Sciences, 5, 1272-1279. http://dx.doi.org/10.4236/fns.2014.513138
The full study can be read here.