Melissa Izabel Hannas

Nine male pigs, which average 44.8 ± 3.6 kg body weight, were surgically fitted with a T cannula in the terminal ileum of the small intestine. The animals were assigned to a triplicated 3 × 2 incomplete Latin square design, consisting of three treatments: a complete mixture of industrial amino acids (L‐AAs), a single cell protein (SCP) biomass coproduct, and an nitrogen‐free diet. The animals were fed twice a day, with 5 days of adaptation to the experimental diets, followed by 2 days of continuous collection of ileal digesta for 10 h. Titanium dioxide was included in all diets at 0.5% as an indigestibility marker, and the N‐free diet was used to estimate basal endogenous ileal losses of amino acids (AA). The standardized ileal digestibility (SID) of crude protein was higher ( p < 0.05) for L‐AAs compared to SCP (101.3% vs. 73.4%). For the indispensable and dispensable AA, the L‐AAs also presented higher SID ( p < 0.05) to SCP. Specifically for L‐tryptophan, the SID of SCP was 89.2%. These results highlight that L‐AAs are highly digestible, with SID values close to 100%, whereas SCP demonstrates viability as a source of indispensable and dispensable AA in swine nutrition.

A 10-day study was carried out to evaluated the effects of organic (zinc proteinate, ZnPro) and inorganic (zinc sulfate, ZnSO₄•H₂O) zinc supplementation on growth, tissue mineralization, mineral excretion, and antioxidant responses in broiler chickens. Male Cobb 500 chicks were allotted into 10 treatments, and ten replicates per treatment with five birds per replicate in a 2 × 5 factorial design. Dietary Zn was supplied at 0, 19, 38, 57, and 76 mg/kg. ZnPro feeds included proteinates for copper, iron, and manganese, while Zn-sulfate diets used inorganic salts. Results  Body weight (BW) and average daily gain (ADG) improved at 19 mg Zn/kg for both sources. Feed conversion ratio (FCR) was optimized at 19 mg Zn/kg for ZnPro and 30 mg Zn/kg for Zn-sulfate. Interactive effect was observed for Zn intake, excretion and retention. At higher inclusion of ZnPro levels (≥ 38 mg Zn/kg), chicks showed increased Zn intake and excretion. ZnPro levels higher than ≥ 56 mg Zn/kg promoted higher Zn retention. Zn retention in liver and tibia were maximized at 38 mg Zn/kg for both sources, and were similar until 76 mg Zn/kg. ZnPro resulted in higher liver Zn concentration and greater tibia manganese (Mn) deposition, while Zn-sulfate increased liver iron (Fe) concentration. Additionally, Zn-sulfate enhanced glutathione peroxidase (GSH-Px) activity in liver and breast muscle, while both sources modulated liver superoxide dismutase (SOD) activity. Conclusions  Both Zn sources supported growth and antioxidant responses, with optimal DWG levels at 30 mg Zn/kg for Zn-sulfate and 19 mg Zn/kg for ZnPro, highlighting greater efficiency of the organic source. Inorganic Zn further boosted GSH-Px activity, enhancing tissue antioxidant capacity, while ZnPro demonstrated advantages in tissue mineral retention. Further research on environmental impacts of Zn excretion from high ZnPro diets is recommended.

Two trials evaluated the effects of dietary protease inclusion in weaned piglets fed diets with or without crude protein (CP) reduction, focusing on performance, intestinal health, and amino acid digestibility. In Trial I, 270 piglets (21–63 days) received six treatments: control (PC), PC with 100 g/ton protease A (PC+A), CP reduced by 1.0% (NC1) or 1.5% (NC1.5), NC1.5 with 50 g/ton protease A (NC1.5+A), and NC1.5 with 50 g/ton protease B (NC1.5+B). PC+A improved weight gain, feed intake, and feed conversion compared with NC1.5+A. The incidence of diarrhea was reduced in animals fed protease-supplemented diets (PC+A, NC1.5+A and NC1.5+B). PC had greater ileal villus height than NC1.5+B, and PC+A showed a higher jejunal villus-to-crypt ratio than reduced CP groups. NC1.5+B increased jejunal expression of IL-6, TNF-α, and haptoglobin. In Trial II, 12 ileal-cannulated piglets received diets with or without protease A. Protease improved the standardized ileal digestibility (SID) of methionine+cysteine and tryptophan but reduced the SID of glycine and proline. While protease supplementation can improve some amino acids (Met+Cys and Thr) protein digestibility, our findings suggest it cannot fully replace careful amino acid balancing in CP-reduced diets. However, protease-supplemented diets were associated with improved intestinal morphometry and a reduced incidence of diarrhea.

This study aimed to evaluate the effects of the standardized ileal digestible tryptophan-to-lysine (SID Trp–Lys) ratio through the supplementation of different levels of L-tryptophan on pig performance and immune response following an LPS challenge. A total of 120 entire male pigs, with an average body weight of 16.5 ± 0.50 kg, were allocated in a randomized block design with four treatments, ten replicates per treatment, and three animals per experimental unit. The experimental treatments consisted of SID Trp–Lys ratios of 16%, 18%, 21%, and 24%, achieved through L-tryptophan supplementation. The evaluated performance parameters included the final body weight (BW), average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR). Blood samples were collected on day 21 to determine serum serotonin levels, and on day 26, pigs were inoculated with LPS to induce an immune challenge, followed by blood sampling to assess cytokine responses. The results showed that pigs fed the 16% SID Trp–Lys ratio exhibited a lower FBW (p < 0.05). The SID Trp–Lys ratios influenced performance parameters, with quadratic responses (p < 0.05) observed for the FBW and FCR, where the highest FBW and lowest FCR were recorded at 22.05% and 21% SID Trp–Lys, respectively. A linear increase (p < 0.05) was observed for ADG, with a trend for a linear increase (p = 0.056) in ADFI. No effects (p > 0.10) of the SID Trp–Lys ratios were detected on serum serotonin levels. An increase in cytokine levels (GM-CSF, IFN-γ, IL-1α, IL-1β, IL-1ra, IL-4, IL-6, IL-8, IL-10, IL-12, IL-18, and TNF-α) was observed in pigs challenged with LPS (p < 0.10) compared to non-challenged animals. An interaction effect (p < 0.10) was detected for IL-2 and IL-18. SID Trp–Lys ratios between 21% and 24% optimize growth performance in pigs from 16 to 33 kg and modulate the immune response under LPS-induced challenge conditions.

The corn-based ethanol production industry provides co-products with potential value as animal feed. However, the nutritional value of these co-products should be adequately determined for their sustainable implementation in swine diets. Therefore, a study was conducted to determine the concentration of amino acids (AA), apparent ileal digestible amino acids (AID), standardized ileal digestible amino acids (SID), and crude protein (CP) in corn distillers dried grains with high protein content (corn HP-DDG) for pigs. Six growing pigs (initial body weight: 46.30 ± 2.14 kg) were surgically fitted with a T-cannula at the distal ileum and allotted to a duplicate 2 × 3 incomplete Latin Square Design. Diets containing corn HP-DDG as the only AA source and a nitrogen-free diet (NFD) were formulated. Corn HP-DDG was used as a test ingredient to replace 40% of the starch in NFD, and titanium dioxide (0.5%) was added as an indigestible marker to both diets. Pigs were fed between 08:00 and 18:00 h during five days of adaptation and a sequence of two days of ileal digesta collection. On an as-fed basis, the chemical composition of corn HP-DDG was 40.41% CP, 1.39% lysine, 1.57% methionine + cysteine, 1.61% threonine, 0.23% tryptophan, and 2.15% valine. The AID and SID values of corn HP-DDG were 74.04% and 80.87% for CP; 76.32% and 79.15% for lysine; 84.75% and 86.52% for methionine + cysteine; 71.97% and 78.30% for threonine; 83.86% and 92.44% for tryptophan; and 76.34% and 80.47% for valine, respectively. In conclusion, the SID CP and AA in corn HP-DDG were within the previously published values, and the determined SID coefficients should be used to formulate accurate diets for pigs.