We conducted an experiment with 289 primiparous sows to evaluate the effect of lysine intake on lactation and subsequent reproductive performance. Sows were randomly allotted to one of five experimental corn-soybean meal lactation diets. The first four diets contained incremental levels of apparently digestible lysine (.67, .86, 1.06, and 1.25%) and provided digestible lysine intakes of 27, 34, 41, and 48 g/d. All lysine was derived from intact protein sources. Synthetic valine, threonine, and methionine were used to maintain ratios to lysine that were equal to those of the .67% lysine diet. The fifth diet contained 1.06% digestible lysine and provided 43 g/d digestible lysine, but no additional synthetic amino acids were added. The average lactation length in this study was 16.9 +/- .2 d. Lysine intake during lactation did not affect number of pigs weaned, litter growth rate, sow backfat loss, or weaning to mating interval. Sow weight loss and loin eye area loss decreased quadratically (P < .05) with increasing lysine intake. These were minimized at 45 and 48 g/d digestible lysine, respectively. Removing synthetic amino acids from the 1.06% digestible lysine diet resulted in an increased litter growth rate (1.98 vs 2.15 kg/d, P < .05). Increasing dietary lysine intake while maintaining amino acid ratios to lysine for valine, threonine, and total sulfur amino acids during the first lactation resulted in a linear (P < .05) decrease in second litter total born. However, removal of synthetic amino acids from the 1.06% digestible lysine diet resulted in an increased second litter total born (12.9 vs 11.2, P < .05), which tended to be higher compared with the .67% digestible lysine treatment (12.9 vs 11.7, P = .13). The results suggest that primiparous sows are able to mobilize sufficient body reserves to maintain a high level of milk production at low levels of lysine intake during a 17-d lactation. Higher levels (45 to 48 g/d) of digestible lysine are required to minimize body protein loss. The source or composition of amino acids in the lactation diet may have an effect on second litter size.

Four experiments utilizing 49 primiparous and 34 multiparous sows were conducted to evaluate the effect of feeding either starch, soybean oil or medium-chain triglyceride (MCT) during late gestation (d 100 to parturition) on neonatal fasting blood glucose homeostasis (Exp. 1 and 2), d-100 maternal circulating insulin, glucagon and glucose concentrations (Exp. 3 and 4), neonatal energy stores (Exp. 3 and 4) and colostrum composition (Exp. 1, 2, 3 and 4). In all cases, sows were fed 7.2 Mcal/d of a diet that supplied 279 g of protein daily. During fasting, pigs from MCT-fed dams had higher blood glucose concentrations (P less than .05) than pigs from starch-fed dams. No differences between treatments were observed for total carcass fat, liver glycogen or carcass glycogen of pigs killed prior to suckling. In general, colostrum fatty acid profiles were influenced by diet; however, the shifts in fatty acids differed for experiments. Starch-fed sows had higher blood insulin and lower blood glucagon (P less than .05) than lipid-supplemented sows; however, sow blood glucose remained constant across treatments. This study indicates that any positive effects of feeding soybean oil to sows during late gestation are most likely mediated by a change in fatty acid composition of colostrum; any beneficial properties of MCT feeding most likely are mediated through improved blood glucose maintenance of the neonate when it is subjected to fasting conditions.

Animal proteins are commonly used in extruded dog foods. Plant-based proteins have a more consistent nutrient profile than animal sources but may contain antinutritional factors, including trypsin inhibitors and oligosaccharides. Bioprocessed soy protein (SP; HP-300; Hamlet Protein, Inc., Findlay, OH) is a processed soy-based product with low antinutritional factor concentrations and high protein quality. The objective was to evaluate the effects of SP on apparent total tract macronutrient digestibility, fecal characteristics, and fecal fermentative end products. Furthermore, this study aimed to identify if SP can be a replacement for poultry byproduct meal (PBPM) in dog food and determine if there are practical limits to its use. Three palatability experiments were conducted to evaluate 1) 0 vs. 12% SP, 2) 0 vs. 48% SP, and 3) 12 vs. 48% SP. For digestibility, 48 healthy adult Beagle dogs (20 females and 28 males; 3.4 yr mean age and 10.0 kg mean BW) were randomly allotted to 1 of 6 dietary treatments, 0 (control), 4, 8, 12, 24, and 48% SP, in a completely randomized design. All diets were formulated to meet Association of American Feed Control Officials nutrient profiles and contained approximately 30% CP and 16% fat. The treatment period consisted of a 10-d diet adaptation phase followed by a 4-d fresh and total fecal collection phase. The palatability results suggest that of the 3 inclusion levels tested (0, 12, or 48% SP), the best inclusion of SP is 12%, which was preferred over 0 and 48% SP. Digestibility and fecal data were evaluated for linear and quadratic effects using SAS. Stool output (on both an as-is and a DM basis) did not differ from the control except for the 48% SP treatment ( < 0.01). Fecal output per unit food intake differed ( < 0.01) from the control only at the 24 and 48% SP inclusion rates. No significant effects of feeding SP were found on stool consistency scores. Digestibility of DM, OM, and energy did not differ from the control at any inclusion rate, except for a decrease ( < 0.01) at 48% SP. Apparent total tract CP digestibility was not affected by treatment and ranged from 82.9 to 86.2%. Fecal short-chain fatty acid concentrations were greater ( < 0.01) in dogs fed 24 and 48% SP compared with the control. Conversely, branched-chain fatty acid concentrations were lower ( < 0.01) in dogs fed 8 to 48% SP compared with the control. These data suggest that SP is a suitable replacement for PBPM in dog diets up to a 24% inclusion level.

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We conducted an experiment to determine the proportion of the lysine requirement of lactating sows that can be met using L-lysine x HCl. A total of 247 Pig Improvement Company (PIC) sows (parity one to four) were randomly allotted to one of five experimental diets containing .79% apparently digestible lysine. The first four diets contained 0, .075, .150, and .225% L-lysine x HCl replacing the intact lysine, primarily derived from soybean meal. Dietary crude protein was reduced from 17.9 to 16.9, 15.8, and 14.8% respectively. The fifth diet contained .174% L-lysine x HCl (15.5% CP) with added synthetic methionine, threonine, and tryptophan to restore the ratios of these amino acids to lysine to those in the control diet with no synthetic amino acids. The average lactation length was 15.7 +/- .3 d. Diet did not affect ADFI, sow backfat loss, sow loin eye area loss, or weaning-to-mating interval. Sows consumed an average of 4.6 kg/d and were provided 36 g/d of digestible lysine. Replacing soybean meal with increasing levels of L-lysine x HCl did not affect sow weight change. The number of pigs weaned decreased and preweaning mortality increased linearly (P = .08) with increasing levels of L-lysine x HCl. Litters from sows fed the .174% L-lysine x HCl with added methionine, threonine, and tryptophan grew slower and had a higher mortality rate than litters from sows fed no synthetic amino acids (P < .05). The addition of synthetic methionine, threonine, and tryptophan to the .174% L-lysine x HCl diet did not improve litter growth rate, but it did increase preweaning mortality (P = .05) and decrease the number of pigs weaned (P = .06) compared to the .15% L-lysine x HCl with no additional synthetic amino acids. These additions also resulted in an increased sow weight loss (P = .10). These results suggest that when more than .075% L-lysine x HCl is used to meet the lysine requirement preweaning mortality is increased and the number of pigs weaned is decreased. Supplementation with methionine, threonine, and tryptophan failed to ameliorate the negative response associated with L-lysine x HCl, which suggests that other amino acids may be limiting.