Content of plasmatic glycerol and activity of hepatic glycerol kinase in broiler chickens fed diets containing different sources and concentrations of glycerine

Abstract

The objective of this study was to evaluate the effect of three sources of glycerine (crude glycerine from soya bean oil - CGSO, mixed crude glycerine from frying oil and lard--MCG, and a semipurified glycerine from soya bean oil--SPGSO) in four concentrations in the diet (17.5, 35.0, 52.5 and 70.0 g of each type of glycerine per kg of feed) on the levels of plasmatic glycerol and the activity of the hepatic enzyme glycerol kinase in broilers of 22-35 days old (experiment I) and 33-42 days old (experiment II). The highest (p < 0.05) plasmatic glycerol level was detected in broilers fed diet containing CGSO. Independent of the source, increasing the concentration of glycerine led to a linear increase (p < 0.05) in the plasmatic glycerol concentration. In experiment I, all the diets containing glycerine resulted in increased concentrations of plasmatic glycerol, in relation to the control diet without glycerine. However, in experiment II, only the diet containing 17.5 g of CGSO per kg of feed and the diets formulated with any of the three types of glycerine in the inclusion concentrations of 35, 52.5 and 70 g/kg of feed resulted in higher plasmatic glycerol levels than those observed in the control broilers. The source of glycerine influenced the glycerol kinase activity only in experiment II, where the use of CGSO in the diet increased the enzyme activity. For both experiments, the glycerol kinase activity increased with the inclusion of glycerine in the diet. In conclusion, based on the absence of saturation of the glycerol kinase activity for the three glycerine sources and for both rearing periods evaluated, the broilers can metabolize the glycerol (at the level of the phosphorylation of the glycerol to glycerol-3-phosphate in the liver) present in the glycerine when the diet is supplemented with up to 70 g of glycerine per kg of feed.

Effects of in ovo feeding with glycerol for broilers

“…The increase in hepatic glycerol kinase activity observed in this study suggests that inoculated glycerol was used by the birds (Bernardino et al, 2014). However, sparing effects of amino acids provided by glycerol and benefits related to the weight at hatching and breast yield were not observed.…”

“…The activity of liver glycerol kinase was assessed using an adaptation of the methodology presented by Bernardino et al. (). For this, 0.5 g of frozen liver tissue was macerated in a Turrax homogenizer (Ultra‐Turrax T‐25 Basic; IKA‐Werke, Staufen, Germany) with 1.0 ml of 0.05 m Tris–HCl buffer (pH 8.0), and then, the sample was centrifuged (15 000 g for 20 min at 5 °C) and the supernatant collected.…”

Mixed crude glycerin in laying hen diets: live performance and egg quality and fatty acid profile

“…McLea et al (2011) showed that 6.7% glycerin increases dietary nutrient utilization; however, feed conversion ratio increases in broiler chickens above this level. While Bernardino et al (2014) did not observe any saturation of the liver enzyme glycerol kinase with the dietary inclusion of up to 7.0% glycerin, this enzyme is probably saturated above this level because the inclusion of 10% glycerin in broiler diets decreases body and breast weight and increases feed conversion ratio (Cerrate et al 2006). Despite the evidence showing that glycerin levels higher than 5% impair broiler performance, the results from the present experiment and several other studies indicate that glycerin levels higher than 5% are not very detrimental for egg production.…”

“…In the diet, glycerol is generated from triacylglycerides in dietary fat. Crude glycerol or glycerol resulting from digestion of triacylglycerides is passively and actively absorbed in the intestine (Kato et al, 2004;Ohta et al, 2006) and transported to the liver by the bloodstream (Bernardino et al, 2014).…”

Metabolism of glycerol in pigs fed diets containing mixed crude glycerin and β-adrenergic agonist

“…Em frangos de corte, Bernardino et al (2014) encontraram respostas semelhantes, com aumentos no teor de glicerol plasmático com o fornecimento de rações contendo de 0 a 7% de glicerina. Estes resultados demonstram a absorção intestinal do glicerol presente na glicerina e seu transporte até o fígado de monogástricos (TAO et al, 1983).…”