The effects of partially replacing animal protein sources with full fat black soldier fly larvae meal (Hermetia illucens) in nursery diets on growth performance, gut morphology, and immune response of pigs

One hundred and forty-four newly weaned pigs (6.74 ± 0.23 kg initial BW; 21 days of age) were used to determine the effect of partially replacing animal protein sources with black solider fly larvae meal (BSFLM) in nursery diets on growth performance, gut morphology, and immune response. After weaning, pigs were placed in 24 pens (6 pigs per pen) and pens were randomly assigned to one of four dietary treatments (study d 0; n = 6), which were fed over 3 phases (phases I, II, and III were fed for 7, 14, and 21 days, respectively). Two nursery diets were formulated with 25% (LowFF) and 50% (HighFF) of the animal protein sources replaced by full fat BSFLM. Conventional nursery diets including animal protein sources without (CON-) and with antibiotics (220 mg Aureomycin per kg of complete feed; CON+) served as controls. On day 8, two pigs per pen were sacrificed to collect organ weights and for intestinal histomorphological measurements. On days 9 and 23, two pigs per pen were vaccinated with the novel antigen ovalbumin (OVA). Blood samples were collected on days 9, 23, and 38 to assess concentrations of plasma haptoglobin and OVA-specific immunoglobulins G (IgG) and IgG1. On day 38, the same two pigs per pen underwent a dermal hypersensitivity test and skin-fold thickness was measured at 0, 6, 24, and 48 h post-intradermal injection with OVA. Pigs fed the CON- had greater ADFI and lower G:F in phase 2 versus those fed CON+ and HighFF diets (P < 0.05 and P < 0.05); intermediate ADFI was observed for pigs fed the LowFF diet. Overall in the nursery period, ADG (496 ± 13 g), ADFI (743 ± 23 g), G:F, and final BW (27.61 ± 0.66 kg) were not different among dietary treatments. There were no differences in organ weights, jejunal or ileal villus heights, or crypt depths among dietary treatments. There were no differences in OVA-specific IgG, IgG1, or plasma haptoglobin among dietary treatments at any of the blood sampling times. Although not different, pigs fed the LowFF, HighFF, and CON+ diets had respectively 2.0, 1.7, and 1.4× greater dermal hypersensitivity response to OVA versus those fed CON-. Both inclusion levels of BSFLM in nursery diets supported growth performance, gut morphology, and indices of immune function not different from the CON+, which suggest that full fat BSFLM can replace at least 50% of animal protein sources in nursery diets of pigs without any deleterious effects on pig growth.

Digestible threonine-to-lysine ratio for piglets under health challenge

Aiming to determine the ration between digestible lysine and digestible threonine (Thr/Lys) for weaned piglets at 27 days, kept in the nursery under sanitary challenge conditions, 105 hybrid piglets with initial weight of 7.2 ± 0.41 kg, were distributed in randomized block design inside of five treatments (Thr/Lys ratios of 0.56; 0.63; 0.70; 0.77 and 0.84), seven replicates and three piglets per experimental unit. The Thr/Lys ratios did not affect (P>0.05) piglet performance. There was quadratic effect (P=0.02) of the Thr/Lys ratio on the protein/fat ratio and the estimated point of the bigger protein/fat ratio occurred with the Thr/Lys ratio of 0.68. The Thr/Lys ratio did not affect (P>0.05) the carcass parameters and serum urea levels, however, the liver and kidney weights raised with the increase (P=0.01) in Thr/Lys rate. The Thr/Lys ratio had a quadratic effect (P=0.01) on rate of plasma haptoglobin, Thr/Lys ratio was estimated at 0.74. It was concluded that the ratio between digestible threonine with digestible lysine for piglets from 27 to 48 days of age raised under sanitary challenge conditions is 0.74.

PSXII-9 The effects of DFM plus tannins on measures of immunity and growth performance of weaned beef calves

A two-year study was conducted to determine the effects of direct-fed microbials plus tannins (DFM + TN) on weaned calf performance and indicators of innate immune response. Angus calves (n = 142 year 1; 143 year 2) were weaned at 6 months of age, transferred to a feedlot, and fed one of two diets for 42 days: a ration with added DFM + TN (2×108 Propionibacterium acidipropionici; 5×107 CFU/hd/day Lactobacillus animalis; 5×107 CFU/hd/day Bifidobacterium animalis; and tannins 15 g/hd/day) or a ration with no added DFM +TN (CON). Body weights were taken on consecutive days and averaged at the beginning and ending of the study, while single day weights were taken on d 14, and 28. Upon completion of the feeding study (year 2), calves (n = 72) were transported to Laramie, WY (204 km), where blood samples were taken on d 0, 2, 4, 7, and 9 relative to transportation to measure plasma haptoglobin. Data were compared among groups using a categorical response mixed model. The model included the fixed effect of treatment group and the data were measured repeatedly. DFM + TN calves had lower overall (P = 0.001) F:G and tended to have greater ADG (P = 0.15) and lower F:G (P = 0.12) during the first 28 days and greater overall ADG (P = 0.06) and greater (P = 0.11) total gain overall. There was a tendency (P = 0.09) for a treatment x day effect for DFM + TN calves to have lower plasma haptoglobin concentration on day 0 and 4 than CON calves. Weaned calves fed DFM + Tannins tended to have greater growth performance during the first 42 days post weaning and tended to have a reduction in plasma haptoglobin concentrations, suggesting a reduction in stress and a positive impact on calf growth.

The immune response of bats differs between pre-migration and migration seasons

Maintaining a competent immune system is energetically costly and thus immunity may be traded against other costly traits such as seasonal migration. Here, we tested in long-distance migratory Nathusius’ pipistrelles (Pipistrellus nathusii), if selected branches of immunity are expressed differently in response to the energy demands and oxidative stress of aerial migration. During the migration period, we observed higher baseline lymphocyte and lower neutrophil levels than during the pre-migration period, but no stronger response of cellular effectors to an antigen challenge. Baseline plasma haptoglobin, as a component of the humoral innate immunity, remained similar during both seasons, yet baseline plasma haptoglobin levels increased by a factor of 7.8 in migratory bats during an immune challenge, whereas they did not change during the pre-migration period. Oxidative stress was higher during migration than during pre-migration, yet there was no association between blood oxidative status and immune parameters, and immune challenge did not trigger any changes in oxidative stress, irrespective of season. Our findings suggest that humoral effectors of the acute phase response may play a stronger role in the first-line defense against infections for migrating bats compared to non-migrating bats. We conclude that Nathusius’ pipistrelles allocate resources differently into the branches of their immune system, most likely following current demands resulting from tight energy budgets during migration.

397 Effect of Smartamine M on acute phase protein response in receiving beef heifers

Methionine supplementation can improve immune function in transition dairy cattle. Our objective was to determine if supplemental methionine could reduce acute phase protein responses in newly received growing cattle. 384 crossbred heifers (222 kg initial BW; southeastern U.S. origin) were received in 4 truckloads (blocks) over 9 d. BW was measured at arrival. The following day (d 0) cattle were vaccinated for viral and clostridial diseases, received Draxxin (2.5 mg tulathromycin/kg BW), and were stratified within block by arrival BW to 1 of 8 pens containing 12 animals each. Cattle (in 32 total pens) were limit-fed at 2.2% of BW daily (DM basis) a ration containing 40% Sweet Bran, 34.5% dry-rolled corn, 10% corn silage, 7.5% supplement, 4% alfalfa hay, and 4% prairie hay. Within blocks, pens were assigned to 1 of 2 treatments: 0 (control) or 10 g/d Smartamine M (SM) to provide 6 g/d metabolizable methionine. Pen weights were collected weekly to adjust feed offered the following week. Individual BW and tail-vein blood samples were collected on d 0, 14, and 45. Plasma haptoglobin was measured to assess acute phase protein response. Incidences of morbidity (1.6% for control, 2.6% for SM) and mortality (0.5% for both control and SM) were low. Between d 0 and 45, no differences were observed for ADG (1.24 vs. 1.27 kg/d; control vs. SM, P = 0.55) or G:F (0.107 vs. 0.110, P = 0.28), but DMI was 1.3% greater (P < 0.01) for control than SM due to differences in diet DM. An interaction between treatment and linear effect of day was detected for plasma haptoglobin (P < 0.05); over time, haptoglobin increased more for control (2.15, 2.28, and 2.95 mg/mL at 0, 14, and 45 d) than for SM (2.35, 2.37, and 2.58 mg/mL). Supplemental methionine may alleviate acute phase protein responses in stressed receiving cattle.

Association of plasma haptoglobin concentration and other biomarkers with bovine respiratory disease status in pre-weaned dairy calves

We conducted a nested, case-control study of pre-weaned dairy calves ( n = 477; 4 California dairy farms) to assess the association between bovine respiratory disease (BRD) and hematologic biomarkers, including plasma haptoglobin (Hp) and plasma bactericide (PB). At each location, heifer or bull dairy calves were observed 2–4 times per week until confirmed as BRD-positive using parallel interpretation of thoracic ultrasound examination and auscultation. In addition, control calves were enrolled after being confirmed as BRD-negative using ultrasound and auscultation. Complete blood counts (CBC), PB, and Hp concentrations were measured. Hp values were higher in calves with confirmed BRD than in controls ( p < 0.01). The area under the curve (AUC) for the various biomarkers was obtained from the corresponding receiver operating characteristic curves. The AUC for Hp was 0.68, a value greater than those for PB or the remaining CBC parameters, indicating that Hp may be the most useful biomarker of BRD in pre-weaned dairy calves. The cutoff value for Hp was 0.195 g/L.