No abstract

This study aimed to evaluate the effect of supplementing arginine (Arg) + glutamine (Gln) replacing antibiotics on performance, immune response, and antioxidant capacity of pigs in the growing phase. One hundred and fifty 63-d-old pigs with initial body weight (BW) of 25.0 ± 1.46 kg were distributed in a randomized block design, with three treatments and ten replicates. The three diets were control; antibiotic, control + 100 mg/kg tiamulin and 506 mg/kg oxytetracycline; amino acid, control + 10 g/kg Arg and 2 g/kg Gln. Dietary treatments were fed from 63 to 77 d. Following the treatment period, all pigs were fed the control diet from 77 to 90 d. Data were analyzed using GLIMMIX and UNIVARIATE in SAS 9.4. From 63 to 70 d, pigs fed diets with antibiotics had improved (P < 0.05) average daily feed intake (ADFI), average daily weight gain (ADG), gain to feed ratio (G:F), and 70 d BW compared to those fed control or amino acid diets. From 70 to 77 d, including antibiotics in the diet increased (P < 0.05) ADG and 77 d BW. From 77 to 90 d, pigs fed the amino acid diet had greater (P < 0.05) ADG and ADFI than those fed an antibiotic diet. From 63 to 90 d, although pig performance was not affected (P > 0.05), growth curve of pigs fed the antibiotic diets was different (P < 0.05) from those fed the control and amino acids diets. At 70 d, serum tumor necrosis factor-α and diamine oxidase (DAO) were lower (P < 0.05) in pigs fed the antibiotic diet than the control diet, and pigs fed the amino acid diet had intermediate results. Ferric reducing antioxidant power (FRAP) was lower (P < 0.05) in pigs fed the amino acid diet than the antibiotic diet, and pigs fed the control diet had intermediate results. At 70 and 77 d, serum urea nitrogen was higher (P < 0.05) in pigs fed the amino acid diet. At 77 d, DAO and serum immunoglobulin G was lower (P < 0.05) in pigs fed the antibiotic diet. FRAP was lower (P < 0.05) in pigs fed the amino acid and control diets. Serum malondialdehyde was higher (P < 0.05) in pigs fed the amino acid diet than those fed the control diet, and pigs fed the antibiotic diet had intermediate results. At 90 d, antibiotics or amino acids did not affect (P > 0.05) serum parameters. Amino acid blend supplementation at the selected doses in this study did not positively affect growing pigs. Although from 63 to 77 d, antibiotics improved performance, when considering the overall study period, growing pigs did not benefit from a diet containing antibiotics.

To evaluate the effects of temporary dietary lysine restriction on nursery pigs’ growth performance and its economic viability compared to control diets, 144 piglets (21-d-old) were assigned to randomized blocks, with two treatments and twelve replicates. The treatments were control-lys: lysine level as recommended from 21-32 and 32-42 days and low-lys: 90% of the lysine level of the control-lys diets. From 42 to 62 days, all animals received a control diet. From 21 to 32 days, pigs fed low-lys had worse average daily gain (ADG), feed conversion, and 32-d body weight (BW; P ≤ 0.05). From 32 to 42 days, pigs fed low-lys had lower average daily feed intake, ADG, and 42-d BW (P ≤ 0.05). From 42 to 62 days, pigs had similar performance (P > 0.05). Overall (21 to 62 days), pigs fed the low-lys had lower (P <0.05) ADG and final BW. At 27 and 29 days, pigs fed the low-lys diet had a higher (P≤0.05) incidence of diarrhea. The lowest feed cost and the highest economic efficiency index were recorded for the low-lys treatment. However, pigs fed the control-lys presented a 3.9% higher profitability. In conclusion, a temporary reduction of lysine in the diets of nursery pigs followed by an unrestricted diet in the subsequent period led to worse growth performance and lower economic viability.

This study investigated the effects of L-glutamine and L-glutamate (Gln/Glu) on growth performance and intestinal health of nursery pigs fed low digestible lysine diets. Piglets (n = 150; 21-day-old; 5.6 ± 0.55 kg initial BW) were distributed in a randomized block design, with three treatments and ten replicates. Experimental diets were fed from 21 to 33 and 33 to 47 d of age. The treatments consisted of control, standard lysine level; low-lys, 90% of the lysine level of the control diets; low-lys + Gln/Glu, low-lys diets supplemented with 1.2% and 0.8% of Gln/Glu (AminoGut, Ajinomoto) per phase. Alanine, inert and starch were used to make treatments isoproteic and isocaloric. Data were analyzed with SAS 9.4 PROC GLM. From 21 to 33 d, pigs fed control or low-lys + Gln/Glu diets had improved ADG, G:F, and 33-d BW compared with those fed low-lys diets (P &lt; 0.05). From 21 to 47 d, pigs fed control or low-lys + Gln/Glu diets had improved ADG and 47-d BW compared with those fed low-lys diets (P &lt; 0.05). The supplementation of Gln/Glu in the diets improved G:F compared with those fed low-lys (P &lt; 0.05). Pigs fed low-lys + Gln/Glu had greater duodenum villus height compared with those fed low-lys (P &lt; 0.05), and pigs fed the control diet had intermediate results. Pigs fed control diets had increased presence of goblet cells in duodenum compared with those fed low-lys (P &lt; 0.05), and pigs fed the low-lys + Gln/Glu diet had intermediate results. Pigs fed low-lys + Gln/Glu diets had increased presence of goblet cells in jejunum compared with the other treatments (P &lt; 0.05). The diets did not influence Peyer's patches count (P &gt; 0.05). In conclusion, supplementation of Gln/Glu on low lysine diets improved nursery pigs growth performance and intestinal heath.