Evaluation of Different Vitamin Concentrations on Grow-Finish Pig Growth and Carcass Characteristics

Vitamins are generally added to swine diets in concentrations well above their requirement estimates to provide a generous margin of safety. However, with the increase in vitamin prices in 2017, there was a need to re-evaluate suggested vitamin additions. Therefore, the objective of this study was to compare two premixes with different vitamin concentrations on growth performance and carcass characteristics of grow-finish pigs reared in a commercial environment. A total of 1,188 pigs (PIC 359 × 1050; initially 35.5 lb) were used in a randomized complete block design with 27 pigs per pen and 22 pens per treatment. The experimental diets were corn-soybean meal-DDGS-based and were fed in 5 phases from approximately 35 to 60, 60 to 110, 110 to 165, 165 to 220, and 220 to 280 lb. There were two dietary treatments based on different vitamin concentrations. The first was the Kansas State University recommended vitamin premix up to December 2017. It contained 1,600,000 IU vitamin A; 400,000 IU vitamin D, 8,000 mg vitamin E; 800 mg vitamin K; 7 mg vitamin B12; 15,000 mg niacin; 5,000 mg pantothenic acid; and 1,500 mg riboflavin. The second was the K-State recommended vitamin premix since January 2018. It contained: 750,000 IU vitamin A; 300,000 IU vitamin D; 8,000 mg vitamin E; 600 mg vitamin K; 6 mg vitamin B12; 9,000 mg niacin; 5,000 mg pantothenic acid; and 1,500 mg riboflavin. Overall (d 0 to 138), there was no evidence for differences in average daily gain (ADG), average daily feed intake (ADFI), or feed efficiency (F/G). Also, no evidence for differences was observed for final weight, hot carcass weight or any other carcass characteristic. In conclusion, the new K-State 2018 recommended vitamin premix concentrations provided similar growth performance as the 2017 recommendations, while not influencing carcass traits in grow-finish pigs.


Summary
Vitamins are generally added to swine diets in concentrations well above their requirement estimates to provide a generous margin of safety. However, with the increase in vitamin prices in 2017, there was a need to re-evaluate suggested vitamin additions. Therefore, the objective of this study was to compare two premixes with different vitamin concentrations on growth performance and carcass characteristics of growfinish pigs reared in a commercial environment. A total of 1,188 pigs (PIC 359 × 1050; initially 35.5 lb) were used in a randomized complete block design with 27 pigs per pen and 22 pens per treatment. The experimental diets were corn-soybean meal-DDGSbased and were fed in 5 phases from approximately 35 to 60, 60 to 110, 110 to 165, 165 to 220, and 220 to 280 lb. There were two dietary treatments based on different vitamin concentrations. The first was the Kansas State University recommended vitamin premix up to December 2017. It contained 1,600,000 IU vitamin A; 400,000 IU vitamin D, 8,000 mg vitamin E; 800 mg vitamin K; 7 mg vitamin B 12 ; 15,000 mg niacin; 5,000 mg pantothenic acid; and 1,500 mg riboflavin. The second was the K-State recommended vitamin premix since January 2018. It contained: 750,000 IU vitamin A; 300,000 IU vitamin D; 8,000 mg vitamin E; 600 mg vitamin K; 6 mg vitamin B 12 ; 9,000 mg niacin; 5,000 mg pantothenic acid; and 1,500 mg riboflavin. Overall (d 0 to 138), there was no evidence for differences in average daily gain (ADG), average daily feed intake (ADFI), or feed efficiency (F/G). Also, no evidence for differences was observed for final weight, hot carcass weight or any other carcass characteristic. In conclusion, the new K-State

Introduction
Added vitamins in swine diets are essential for optimal growth performance. Vitamins serve as co-factors in many different metabolic processes, such as bone mineralization, enzymatic activities, and tissue maintenance. It is a common practice to provide added 1 Appreciation is expressed to New Horizon Farms (Pipestone, MN) for providing research facilities. dietary vitamins greater than the daily requirement estimate as a safety factor and to account for potential losses from feed manufacturing errors and prolonged premix storage. Many vitamins have been inexpensive, and thus high margins of safety have been used. However, due to changes in world vitamin supply in 2017, particularly with vitamin A and others, premix prices increased substantially, thus raising the question about whether current margins were necessary.
Therefore, the objective of this study was to compare two different vitamin premixes with a high or low margin of safety on growth performance and carcass characteristics for grow-finish pigs raised under commercial conditions.

Procedures
The Kansas State University Institutional Animal Care and Use Committee approved the protocol used in this experiment. The study was conducted at a commercial research facility in southwestern Minnesota. The barn was naturally ventilated and double curtain-sided. Each pen was equipped with a 4-hole stainless steel dry self-feeder and a cup waterer for ad libitum access to feed and water. Feed additions to each individual pen were made and recorded by a robotic feeding system (FeedPro, Feedlogic Corp., Wilmar, MN).
A total of 1,188 pigs (PIC 337 × 1050, initially 35 lb) were used in a 138-d growth trial with 27 pigs per pen and 22 pens per treatment. Pigs were allotted to treatments based on initial body weight (BW) in a randomized complete block design.
The experiment included two dietary treatments. The first treatment contained the K-State recommended vitamin premix up to December 2017. The second treatment contained the new K-State recommended vitamin premix as of January 2018. The January 2018 premix contained lower levels of vitamins A, D, K, niacin, and B 12 than the December 2017 recommendations (Table 1).
The experimental diets were based on corn, distillers dried grains with solubles (DDGS), and soybean meal. Diets were fed in 5 different phases from 35 to 60, 60 to 110, 110 to 165, 165 to 220, and 220 to 280 lb ( Data were analyzed using a linear mixed model with treatment as fixed effect, block as random effect, and pen as the experimental unit. Hot carcass weight was used as a covariate for analyses of backfat, loin depth, and lean percentage. Statistical models were fitted using the GLIMMIX procedure of SAS version 9.4 (SAS Institute Inc., Cary, NC). Results were considered significant at P ≤ 0.05.
For overall growth performance, there was no evidence for differences (P > 0.05) in ADG, ADFI, or F/G (Table 3). During phase 3 (110 to 165 lb) pigs experienced a Haemophilus parasuis outbreak. During that time, ADFI and ADG decreased and mortality increased, but no differences among treatments were observed. There was a tendency (P ≤ 0.10) for increased final body weight and HCW for pigs fed the December 2017 premix levels; however, this advantage was caused by a numeric increase in removal of lightweight pigs from that treatment and not by an increase in growth rate. Total pen gain and total feed intake also showed no evidence for differences between treatments. For carcass characteristics, no evidence for differences (P > 0.05) was observed for carcass yield, backfat thickness, loin depth, or percentage lean. Mortality and percentage of pigs removed from the study due to poor growth were not different between the two treatments.
In conclusion, new 2018 K-State vitamin premix recommendations and dietary levels for grow-finish pigs did not influence growth and carcass traits compared with the 2017 recommendations. The decrease in the historical margin of safety for vitamins to levels in the 2018 premix allows nutritionists and producers to reduce feed cost.   Provided per lb of premix: 1,600,000 IU vitamin A acetate; 400,000 IU vitamin D; vitamin E (8000 mg dl-αtocopheryl acetate); 800 mg vitamin K (menadione); 7 mg vitamin B 12 ; 1,500 mg niacin; 5000 mg pantothenic acid; and 1,500 mg riboflavin. 3 Provided per lb of premix: 750,000 IU vitamin A acetate, 300,000 IU D, vitamin E (8000 mg dl-α-tocopheryl acetate), 600 mg vitamin K (menadione), 6 mg vitamin B 12 , 9,000 mg niacin, 5,000 mg pantothenic acid, and 1,500 mg riboflavin. 4 ADG = average daily gain. ADFI = average daily feed intake. F/G = feed efficiency. HCW = hot carcass weight. 5 Total gain and total feed intake were calculated on a pen basis. 6 Adjusted for HCW as a covariate.