Kansas State University(KSU) researchers conducted two trials to evaluate pyridoxine or thiamin in weanling pig diets. Thiamin and pyridoxine are two B-vitamins that are abundant in grain-soybean meal diets.

Recently several breeding stock companies and vitamin manufacturers have suggested adding thiamin (vitamin B1) and pyridoxine (vitamin B6) to diets to achieve maximum growth potential. The KSU researchers set out to evaluate the effects of added thiamin or pyridoxine on weanling pig growth performance by conducting two experiments.

The first experiment utilized 180 weanling pigs (initially weighing 11.02 lb. and 21 days of age). Each treatment (in both experiments) had six pigs per pen and six pens per treatment.

All experimental diets were fed in meal form. Diets fed from day 0-14 after weaning contained 1.6 "percent" lysine, .44 "percent" methionine, .90% "percent" calcium and .80 "percent" phosphorus.

Diets fed from day 14 to 35 contained 1.35 "percent" lysine, .38 "percent" methionine, .85 "percent" calcium and .75 "percent" phosphorus.

The control diet contained a standard vitamin premix without added thiamin or pyridoxine.

Experimental treatments were provided by adding either thiamin mononitrate (2.5 or 5.0 g/ton) or pyridoxine HCL (3.5 or 7.0 g/ton) to the control diet. Pigs were fed the same experimental vitamin concentrations throughout the 35-day study. Pigs were weighed and feed disappearance was determined weekly after weaning to calculate average daily gain(ADG), average daily feed intake(ADFI) and gain/feed(G/F).

ADG increased from day 0 to 14 after weaning with increasing pyridoxine. Pigs fed 3.5 g/ton of added pyridoxine had the greatest ADG.

ADG decreased then increased for pigs fed thiamin. ADG decreased for pigs fed 2.5 g/ton of added thiamin, but was identical between those fed the control diet and 5 g/ton of added thiamin.

ADFI increased then decreased with increasing thiamin and pyridoxine. However, F/G decreased then increased with increasing thiamin. This appeared to be a result of the high feed intake and poor growth of pigs fed 2.5 g/ton of added thiamin, according to KSU researchers. Feed:gain ratio was unaffected by increasing pyridoxine.

Added thiamin or pyridoxine had no effect on ADG or F/G from day 14 to 35 after weaning. However, ADFI increased with increasing pyridoxine.

Pigs fed 2.5 g/ton of added thiamin had decreased ADG for the period from day 0 to 14 after weaning. Pigs fed 5 g/ton had similar ADG to those fed the control diet.

Pigs fed increasing pyridoxine had increased ADFI from day 0 to 35.

Although ADG and F/G were not significantly improved, ADG was numerically highest for pigs fed the diet containing 3.5 g/ton added pyridoxine, reflecting the response from day 0 to 14.

Based on the results of the first experiment, the KSU researchers conducted a second study to determine the pyridoxine requirement of weanling pigs. The second experiment used 216 weanling pigs (initially 13.6 lb. and 21 days of age). This experiment helped determine the optimum level of pyridoxine to maximize growth performance.

The control diet was identical to that used in the first experiment. The experimental treatments were formed by adding pyridoxine at 1, 2, 3, 4, or 5 g/ton. As in experiment 1, pigs were weighed and feed disappearance was determined weekly after weaning to calculate ADG, ADFI and G/F.

Feed samples from both experiments were collected and analyzed for concentrations of thiamin (experiment 1) and pyridoxine (experiments 1 & 2).

Increasing pyridoxine increased then decreased ADG and ADFI from day 0 to 14 after weaning. Pigs fed 3 g/ton of added pyridoxine had the maximum ADG and ADFI. The increases in ADG appeared to be a result of increased feed intake, because increasing pyridoxine had no effect on feed/gain.

Increasing pyridoxine had no effect on pig growth performance from day 14 to 35 or 0 to 35; however, ADG and ADFI tended to numerically increase with increasing pyridoxine.

The researchers conclude the results suggest adding thiamin had no positive effect on growth performance of weanling pigs. However, adding pyridoxine improved ADG and ADFI of pigs from day 0 to 14 after weaning.

Researchers say the data suggest a requirement of 2 - 3 g/ton of added pyridoxine in diets fed from day 0 to 14 after weaning. For practical applications of this research, the segregated early weaning (SEW) and transition diets should contain 3 g/ton of pyridoxine.

Researchers: J.C. Woodworth, R. D. Goodband, J.L. Nelssen, M.D. Tokach, R.E. Musser, J.A. Loughmiller, S.A. Moser, G.S. Grinstead, and P.R. O'Quinn, Kansas State University. Phone Goodband at (913) 532-1228.

Feeding Wheat In Nursery Diets Oklahoma State University researchers recently conducted two growth trials to evaluate Karl hard red winter wheat in nursery diets. The wheat was used as an energy and protein source for 144 early weaned pigs in Phase 2 (day 10 to 38 postweaning) nursery diets.

The study demonstrated these pigs could effectively use hard red winter wheat as a substitute for corn at a level of 50 or 100 "percent" of corn in the diet.

Pigs were weaned at 17-21 days of age and averaged 13.7 lb. at weaning. They were divided in two groups based on initial weight in each trial.

All pigs were fed a common Phase 1 diet containing 1.5% lysine for the first 10 days postweaning. The pigs were housed in an environmentally regulated nursery in pens (4 ft. 11 in. x 5 ft.) with woven wire flooring.

During Phase 2, pigs (18.8 lb. body weight) were fed one of the following diets: a corn-soybean meal control diet, a diet with wheat replacing 50 "percent" of corn, or a diet with wheat replacing 100 "percent" corn.

Experimental diets were fed for four weeks and contained 1.40 "percent" lysine, .90 "percent" calcium and .76 "percent" phosphorus.

Average daily gain and gain:feed increased with the increasing amount of wheat in the diet during the first week of Phase 2. During the second week, no treatment effects were observed.

Pigs fed the diet containing 50 "percent" corn and 50 "percent" wheat had higher gains than pigs fed only corn or wheat as the grain source during the third week.

Feed intake decreased as the amount of wheat increased in the diet, this resulted in a linear increase in gain:feed as the amount of wheat increased.

During the fourth week and during the overall four-week period, average daily gain and gain:feed increased with increasing the level of wheat in the diet.

Researchers: B.Z deRodas, W.G. Luce and C.V. Maxwell, Oklahoma State University. Phone Luce at (405) 744-6058.

Correction: In the story "Pit Additive Tested" published on page 38 of the Dec. 15, 1997, issue of National Hog Farmer, one nozzle/pen was used to spray the product.