Transitioning to net energy: A swine story

Net energy (NE) is one member of the sequence of energy systems which also includes gross energy (GE), digestible energy (DE), and metabolizable energy (ME). It is perhaps the most sophisticated because it attempts to consider more components of the ingredient or diet which normally cannot be used by the pig for maintenance and/or productive purposes. Gross energy makes no such adjustment and therefore has little direct value in diet formulation. Digestible energy corrects for energy which is lost in the feces, and metabolizable energy also adjusts for energy lost in the urine. The data in Table 1 reveal that heat increment averages 22% of gross energy, and ranges from 17 to 28%, across an array of ingredients that are frequently used in commercial pig diets. Interestingly, the range in NE is about 81%, much greater than the range in ME at 55%. At a very crude level, this suggests that NE accounts for more variation among ingredients than does ME; looked at another way, using ME to formulate diets essentially assumes that HI is similar across ingredients and does not need to be considered. Of course, this is not true

An Enzyme BlendImprovedGrowth Performance in Nursery Pigs

The objective of this experiment was to evaluate the effects of dietary xylanase and an enzyme blend (EB:cellulase, ß-glucanase, and xylanase) on nutrient digestibilityand growth performance inweaned pigletsfed a low energy diet. A total of 460 pigsweighing about 6.43 kg were randomly blocked by weight and assigned to 4 treatments, in a 2 × 2 factorial arrangement.There were 12 blocks and 48 pens with 9 or 10 pigs/pen. The diets were based on corn, soybean meal, corn DDGS, andwheat middlings(5 and 10% each fiber ingredientfor wk 1-2 and 3-4, respectively)with or without enzyme supplementation(Huvepharma Inc., St. Louis, MO),with 0.40% titanium dioxide as an indigestible marker. Body weight and feed intake were recorded weekly. Performance data wereanalyzedas repeated measurementsusing the PROC MIXED procedure of SAS (9.4) with pen as the experimental unit. Xylanase (0 or 0.01%), EB(0 or 0.01%), andtheir interactionswereconsidered fixed effects.The EB addition (12.45 vs. 12.08kg; P= 0.044), but not xylanase (12.27 vs. 12.26 kg; P\u3e 0.05), increased body weight. Neither enzymetreatmenthad an impact on ADFI or G:F ratio (P\u3e 0.05). The EB treatmentimproved ADG (482 vs. 466 g; P= 0.024) from wk1-4. There was noenzymeimpact on ATTDof DM, GE, and CP(P\u3e 0.05). Xylanase supplementation tended to reduceATTD of EE (61.05 vs. 62.82%; P= 0.073)and reducedthe ATTD of NDF(46.10 vs. 48.95%), ADF(27.30 vs. 31.71%), and hemicellulose(52.77 vs. 55.23%; P\u3c 0.01). Supplementation of EB improved ATTD of ADF by 22% (32.45 vs. 26.57%; P= 0.001). In conclusion, EB but not xylanaseimproved growth rate in nursery pigsfed a low energy diet, which may not be completelydue tothe improvement in ADF digestibility

Impact of Tylosin Phosphate and Distillers Dried Grains with Solubles on Amino Acid and Energy Digestibility of Diets Fed to Growing Pigs

Eighteen barrows with a T-cannula in the distal ileam were utilized in a study evaluating the impact of tylosin phosphate on amino acid and energy digestibility in cornsoybean meal and corn-soybean meal-distillers dried grains with soluble (DDGS) based diets. There were no interactions between the responses to tylosin phosphate and DDGS (P\u3e0.10). DDGS inclusion reduced the standardized ileal digestibility of most indispensible amino acids (P\u3c0.05) and the apparent ileal digestibility and apparent total tract digestibility of energy. Under the conditions of this experiment, tylosin phosphate did not affect digestibility of amino acids or energy and the inclusion of DDGS did not affect the response to TP