Addition of crude glycerin to pig diets: sow and litter performance, and metabolic and feed intake regulating hormones

Abstract

The continued growth in biofuel production has led to a search for alternative value-added applications of its main by-product, crude glycerin. The surplus glycerin production and a higher cost of feedstuffs have increased the emphasis on evaluating its nutritive value for animal feeding. The aim of this research was to evaluate the effect of the dietary addition of crude glycerin on sow and litter performance, and to determine the serum concentrations of hormones related to energy metabolism and feed intake in sows during gestation and lactation. A total of 63 sows were assigned randomly to one of three dietary treatments, containing 0, 3 or 6% crude glycerin (G0, G3 and G6, respectively) added to a barley-soybean meal-based diet. During gestation, none of the dietary treatments had an effect on performance, while during lactation, glycerin-fed sows consumed less feed than those fed the control diet (3.8 v. 4.2 kg DM/day; P = 0.007). Although lactating sows fed the G3 diet had a higher BW loss than those fed the control diet (−20.6 v. −8.7 kg; P = 0.002), this difference was not reflected in litter performance. In gestation, the inclusion of glycerin did not affect blood concentrations of insulin or cortisol. However, pregnant sows fed diets supplemented with glycerin showed lower concentrations of acyl-ghrelin and higher concentrations of leptin (−55 and +68%, respectively; P < 0.001). In lactating sows, there were no differences between dietary treatments for any of the hormones measured. Pre-prandial acyl-ghrelin concentrations were positively correlated with cortisol concentrations during gestation ( r = 0.81; P = 0.001) and lactation ( r = 0.61; P = 0.015). In conclusion, the inclusion of up to 6% crude glycerin did not affect the performance of sows during the gestation period; however it had a negative effect on the feed intake and weight loss of lactating sows. Moreover, further research is needed to elucidate the potential relationship between glycerin inclusion levels in the diet and the serum concentrations of hormones related to feed intake and energy balance control.Keywords: crude glycerin, feed intake, metabolic hormones, sow ImplicationsAccording to our results, crude glycerin up to 6% could be added to the diet from confirmation of pregnancy without affecting the performance of pregnant sows. Our results also suggest a relationship between the inclusion of glycerin in the diet and the serum concentrations of feed intake regulating hormones, such as acyl ghrelin and leptin; but more studies are needed to increase the understanding of interactions between diet composition and hormone concentration.

The Effect of the Dietary Inclusion of Crude Glycerin in Pre-Starter and Starter Diets for Piglets

“…In a previous work [ 42 ], it was found that there was a a tendency for higher acyl-ghrelin levels in Iberian crossbred pigs from 50 to 100 kg BW fed 10% glycerin, which were associated with a higher feed intake. In addition, pregnant sows fed diets containing glycerin (up to 6%) had lower concentrations of acyl-ghrelin and higher concentrations of leptin at 0 minutes after feeding [ 48 ] suggesting that the dietary supplementation of glycerin may have exerted a satiating effect. However, to our knowledge, the effect of glycerin inclusion on the serum concentration of ghrelin has never been previously described in piglets and requires further research.…”

Feeding Crude Glycerin to Finishing Iberian Crossbred Pigs: Effects on Growth Performance, Nutrient Digestibility, and Blood Parameters

“…Crude glycerin has been used as an energy source to replace cereals in animal diets, thus increasing the supply of raw materials while reducing production costs [ 23 , 24 , 25 ]. Numerous studies have been performed using glycerin in diets at different stages of pig production: in sows [ 5 , 26 ], weaning pigs [ 2 , 9 , 27 ], growing and finishing pigs [ 4 , 28 ]. All of them were carried out with conventional pig genotypes.…”

Performance and Ruminal Parameters of Boer Crossbred Goats Fed Diets that Contain Crude Glycerin

“…The main by-product of the biodiesel industry is crude glycerin, which represents approximately 10% of the biodiesel produced [1]. Crude glycerin has become a potential alternative feed ingredient for livestock in many species including poultry [2], swine [3], cattle [4,5] and small ruminants [6,7].…”