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

Glycerol as a partial replacement for lactose in milk replacer for young dairy calves

Glycerol (glycerin) is increasingly available from biodiesel manufacture and edible oil refining and it has been used successfully in diets for chickens, pigs, and adult cattle; however, less information is available on its nutritional value in young calves. Our objective was to determine the effects on calf growth and health when glycerol replaced a portion of lactose in milk replacer. Holstein calves (12 male, 12 female) born at the University of Illinois dairy unit were assigned alternately to 1 of 2 treatments (24 calves total): control milk replacer or milk replacer supplemented with 15% glycerol in replacement of lactose. The experimental base milk replacer contained greater protein, fat, minerals, and vitamins so that when glycerol was added, the composition would be the same as that of the control, except that glycerol replaced some lactose. Calves were housed in individual hutches bedded with straw, and water was freely available. Starter was offered beginning on d 36. The amount of milk replacer offered was reduced by half on d 43, and calves were weaned at d 49. Calves were fed milk replacers twice daily from d 3 of life. Milk replacers contained 28% protein (all from whey proteins), 2.6% lysine, and 15% fat. Control milk replacer contained 40% lactose, and the glycerol milk replacer contained 25% lactose. Both replacers were reconstituted to 15% solids. Glycerol (liquid) was added to reconstituted base milk replacer at each feeding. During wk 1, milk replacers were fed at a rate of 0.25 Mcal/kg of metabolic body weight (BW) (about 1.5% of BW daily as powder, or approximately 675 g/d) and from wk 2 to 6 at 0.30 Mcal/kg of metabolic BW (about 2% of BW daily, or approximately 900 to 1,200 g/d). Measurements of BW and stature were made weekly through d 56. Calf BW and average daily gain through d 35 (0.66 vs. 0.65 kg/d for controls and glycerol, respectively) did not differ significantly between treatments. Stature measurements (withers height, body length, heart girth) and measures of health (fecal scores, medical treatments) did not differ between treatments. Under the conditions of this experiment, glycerol was an acceptable replacement for at least 37.5% of the total lactose in milk replacer (15% of the formula) if economically favorable.

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

A total of 192 Iberian × Duroc pigs kept under intensive conditions were used to investigate the effects of feeding crude glycerin on growth performance, nutrient digestibility, and blood parameters. Animals were blocked by initial body weight (96.0 ± 11.3 kg) and allotted to pens (16 pigs per pen). Pens were assigned randomly to one of three dietary treatments (four pens per treatment). Dietary treatments contained 0, 5, or 10% of crude glycerin proportionally substituting for wheat (G0, G5, and G10, respectively). Diets were formulated to be isoenergetic and isoaminoacidic. No significant effect of crude glycerin was observed on average daily gain, average feed intake, or feed conversion ratio. The apparent total tract digestibility of dry matter, organic matter, and crude protein was no different between treatments. Total serum protein, albumin, glucose, insulin, and IGF-1 were not affected by glycerin inclusion. In conclusion, crude glycerin up to 100 g/kg can be included in the diets of finishing Iberian crossbred pigs without any negative effect on growth performance, digestibility, or serum metabolic parameters.

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

The aim of this study was to evaluate the effect of the inclusion of crude glycerin in post-weaning diets for piglets on growth performance and digestibility. The study was carried out with a total of 360 piglets over a 39 day period. Animals were blocked by body weight (7.7 ± 0.86 kg) and allotted randomly to one of three dietary treatments containing 0, 2.5 or 5% glycerin (G0, G2.5 and G5, respectively). Considering the whole period, glycerin did not affect the average daily gain. However, the average daily feed intake (ADFI) and the feed conversion ratio (FCR) tended to decrease or decreased linearly as the amount of glycerin increased, respectively (p = 0.060 and p = 0.039). The apparent total tract digestibility (ATTD) of dry and organic matter (DM, OM) increased linearly with increasing glycerin in both periods (p ≤ 0.05). At the end of the study, there were no differences between treatments for any of the hormones measured. In conclusion, the FCR and digestibility of DM and OM were improved although the ADFI tended to be lower when glycerin was included at 5%. Consequently, crude glycerin could be used as an alternative ingredient to partially replace sweet whey and wheat in post-weaning diets.

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

Simple Summary

There is an increasing interest in the use of by-products, such as crude glycerin in animal feeding, and many studies emphasize that the addition of these ingredients can reduce feed costs, avoid environmental problems, and serve as good energy sources for ruminants. However, there is little information available on the replacement of ground corn with crude glycerin in goat diets. We analyzed the effects of replacing corn with crude glycerin up to 150 g/kg of diet on feed intake and growth performance of goats. This substitution reduced consumption, digestibility, and performance.

Abstract

This study aimed to evaluate the effects of four levels of crude glycerin (0, 50, 100, or 150 g/kg on a dry matter basis) on intake, digestibility, production performance, and ruminal parameters for finishing Boer crossbred goats. Thirty-two crossbred, castrated Boer × undefined breed goat kids, with an initial average weight of 17.8 ± 2.2 kg and approximately four months old, were distributed in a completely randomized design, with four treatments and eight repetitions. The dry matter and neutral detergent fiber intakes, both in g/day and percent of body weight, linearly decreased (p ≤ 0.05) with increased inclusion levels of crude glycerin in the diet. The dietary crude glycerin levels linearly decreased (p ≤ 0.01) the digestibility coefficients of ether extract and quadratically increased (p = 0.04) digestibility coefficients of neutral detergent fiber. The final weight, total weight gain, and average daily gain for the animals showed a linear decrease (p ≤ 0.02) as dietary crude glycerin levels increased. The addition of crude glycerin caused a linear increase in ruminal pH (p ≤ 0.01), which ranged from 6.27 to 6.49 for diets with 0 and 150 g/kg crude glycerin, respectively. The concentration of ruminal NH₃–N exhibited a linear decrease as the crude glycerin inclusion levels increased (p ≤ 0.01). Total short-chain fatty acid (SCFA) concentration, individual molar ratio, and the acetate: Propionate ratio in the ruminal fluid of the animals were not influenced (p ≥ 0.07) by the dietary crude glycerin levels. These data indicate that crude glycerin should not be used to replace ground corn in the diets of growing goats that are finished in a feedlot because the substitution reduces the intake and digestibility of several nutrients and decreases performance.