Translational Animal Science最新文献

This study explores the impact of chitosan nanoparticles (CNP) on the performance, nutrient digestibility, blood biochemical, immunity, microbial load, carcass traits, and meat attributes of broilers. A total of 200 7-d-old Cobb chicks were distributed to 4 groups, each replicated 5 times, with 10 birds in each replicate. The experimental diets were as follows: First group was fed a basal diet only (control); 2nd, 3rd, and 4th groups received a basal diet supplemented with 0.2, 0.3, and 0.4 g CNP/kg of feed, respectively. Results showed that the body weight (BW) and body weight gain significantly improved (P < 0.05) in the birds belonging to the 0.4 CNP group compared to the other groups. The best feed efficiency (feed conversion ratio [FCR]) was found in the group supplemented with a 0.4-g CNP/kg diet. The digestibility coefficients for dry matter and crude protein were significantly higher, and ether extract was significantly lower in the 0.4 g CNP/kg group than in other groups (P < 0.05). Broiler birds of the 0.4 CNP group had significantly (P < 0.05) reduced serum cholesterol, AST, and ALT levels. The humoral immunity (increased serum IgG and IgM levels) tended to improve in birds fed 0.3 and 0.4 g CNP/kg of feed. Compared to the control, total bacterial load and coliform count decreased significantly (P < 0.05) by supplementing 0.4 g CNP in the diet. The dressing weight, breast weight, and abdominal fat % were altered in birds receiving dietary 0.4 g CNP/kg. The treatment with CNP at 0.4 g/kg feed enhanced the broiler meat quality by increasing the values for water holding capacity, ABTS [2, 2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid)], DPPH (2,2-diphenyl-1-picrylhydrazyl) while reducing the thiobarbituric acid reactive substances (TBARS) value. Based on the results above, it could be concluded that CNP supplementation at 0.4 g/kg is recommended as a beneficial feed additive for broiler chickens.

This study aimed to evaluate the effects of a blend of different sources of magnesium oxide associated or not with monensin, on productive, ruminal, and nutritional parameters of steers. Eighty-four Nellore steers with an initial body weight (BW) of 367.3 ± 37.9 kg were allocated to one of 28 pens, with three steers per pen. Each pen was considered an experimental unit. Using a completely randomized design with a 2 × 2 factorial arrangement, the following treatments were assigned to each pen: 1) Control (CON)-a basal diet without additive inclusion; 2) Magnesium oxide blend (MG)-basal diet plus a magnesium-based product (pHix-up, Timab Magnesium, Dinard, France) provided at 0.50% of dry matter (DM); 3) Monensin (MON)-basal diet plus 25 mg/ kg of DM of sodium monensin (Rumensin, Elanco Animal Health, Greenfield, IN); and 4) MG association with MON-basal diet plus MG + MON, at the same doses of the individual treatments. The experimental period lasted 100 d. Blood samples were collected on days 0, 13, and 70 to determine d-lactate levels. Daily feed intake was recorded, and animal ingestive behavior was visually observed on days 66 and 67. On day 70, skeletal muscle tissue samples were obtained through biopsy for gene expression analysis. At the end of the experimental period, carcass ultrasonography was conducted. Subsequently, the steers were slaughtered, and rumen epithelium samples were collected for morphometric analysis. The use of monensin, of magnesium oxide blend, and their interactions, were treated as fixed effects, while the pens were considered as a random effect. Statistical differences were considered when P < 0.05. Steers-fed MG-containing diets consumed approximately 0.6 kg more DM per day than those fed diets without this additive (P = 0.01; 11.3 vs. 11.9 kg/d). The inclusion of MG in the diet increased (P = 0.02) the average daily gain. There was a greater Longissimus muscle area (LMA) and LMA per 100 kg of BW (P ≤ 0.03) for steers-fed diets with MG. Steers-fed MON exhibited reduced mRNA expression of the Atrogin-1 and mTOR compared to steers-fed MG + MON diets (MON × MG: P ≤ 0.04). Steers-fed MON had 6.9% greater feed efficiency (P = 0.02). Papillae width was lesser for CON than other treatments (MON × MG: P = 0.02). In conclusion, the magnesium oxide blend improved performance and carcass traits in high-energy feedlot diets, while monensin enhanced feed efficiency, suggesting potential for their use as alternatives or complements in beef cattle nutrition.

Pistachio shell powder is a high-fiber co-product from the pistachio nut industry that may provide energy and nutrients in animal diets, but no data have been reported for the nutritional value of pistachio shell powder when fed to pigs. Two experiments were, therefore, conducted to test the hypothesis that apparent total tract digestibility (ATTD) of gross energy (GE), dry matter (DM), and total dietary fiber (TDF) and concentration of digestible energy (DE) in pistachio shell powder are not different from those in soybean hulls when fed to gestating or lactating sows. In experiment 1, 24 gestating sows were housed in metabolism crates and fed a corn-based basal diet or 2 diets that contained corn and 20% pistachio shell powder or corn and 20% soybean hulls. Sows were fed experimental diets for 13 d with feces and urine being quantitatively collected for 4 d after 6 d of adaptation. In experiment 2, 24 lactating sows were housed in farrowing crates and fed a diet based on corn and soybean meal (SBM) or 2 diets that contained corn, SBM, and 20% of either pistachio shell powder or soybean hulls, and feces were collected for 6 d after 7 d of adaptation to the diets. Results indicated that for gestating sows, the diet containing soybean hulls had greater (P < 0.05) ATTD of DM, GE, and TDF than the diet containing pistachio shell powder. The DE and metabolizable energy (ME) in the pistachio shell powder diet were less (P < 0.05) than in the basal diet and the diet containing soybean hulls. The ME in pistachio shells (2,606 kcal/kg DM) was less (P < 0.05) than in soybean hulls (3,645 kcal/kg DM). When fed to lactating sows, ATTD of DM, GE, and TDF in the diet containing pistachio shell powder was less (P < 0.05) than in the diet containing soybean hulls or in the basal diet. The DE in the diet containing pistachio shell powder was also less (P < 0.05) than in the soybean hulls diet. The DE in pistachio shell powder (1,664 kcal/kg DM) was less (P < 0.05) than in soybean hulls (2,795 kcal/kg DM). In conclusion, the ATTD of DM and GE and the DE in pistachio shell powder were less than in soybean hulls, and inclusion in lactation diets, therefore, needs to be limited.

Heat wave intensity, frequency, and duration are increasing in many regions of the world, including locations where highly productive livestock are raised. There are animal health and welfare, as well as economic impacts from these events. In this study, the physiological responses of grain-fed steers during a high heat load challenge through to recovery in climate-controlled rooms (CCR) were intensively evaluated. Two cohorts of 12 Black Angus steers (BW, 615.4 ± 40.1 kg) sequentially underwent a simulated heatwave event that consisted of 3 phases in the CCR: PreChallenge (5 d duration and temperature humidity index (THI) range of 65 to 71), Challenge (7-d duration and THI 66 to 95 with diurnal cycling), and Recovery (5 d duration and THI 65 to 70). The Challenge period was modeled on a severe heat wave, characterized by 3 very hot days. Individual rumen temperature (RumT, °C) was collected every 10 min, and respiration rate (RR, breaths per minute), panting score (PS), and water usage (L·steer^-1·day^-1) were obtained at multiple time points daily, by trained observers. Individual animal daily DMI was also determined. Morning (0700 hours) rectal temperature (RecT, °C) was measured on days 3, 5, 7 to 13, 15, and 17. Not unexpectedly, RumT, RecT, RR, and PS rose during Challenge and fell rapidly as conditions eased. Conversely, DMI was reduced during Challenge. During the transition between PreChallenge and Challenge, there were abrupt increases in RumT, and RR. It was also very apparent that during Recovery the steers did not return to the baseline PreChallenge state. Compared to PreChallenge, Recovery was characterized by persistent lowered daily mean RumT (P = 0.0010), RecT (P = 0.0922), RR (P = 0.0257), PS (P ≤ 0.0001), and DMI (P ≤ 0.0001). These results provide evidence that these steers have undergone an allostatic response in response to high heat load, and the new adjusted physiological state post-heat event may not be transient.

Supplementing swine diets with phytase increases phosphorus release by approximately 50% from cereal phytates. The increase in phosphorus availability allows for a reduction in dietary phosphorus supplementation from mineral sources and decreases the environmental impact of pork production through a decrease in phosphorus excretion. Superdosing phytase has been reported to boost swine productivity, improve the digestibility of other nutrients, and mitigate the antinutritional effects of phytates. However, there are significant cost differences among phytase products. Bacterial phytases are considered more modern, often with a higher cost of inclusion. A study was conducted with 288 piglets that were 21 d of age and weighed 6.43 ± 0.956 kg. Pigs were divided into four groups. Each group of pigs was fed a different experimental diet varying in phytase source and level: fungal phytase (Aspergillus niger) at 500 FTU/kg of diet, fungal phytase at 2,000 FTU/kg, bacterial phytase (Escherichia coli) at 500 FTU/kg, and bacterial phytase at 2,000 FTU/kg. No differences were found for phytase sources or doses on productivity at 14 and 21 d postweaning. However, piglets supplemented with 2,000 FTUs/kg of phytase in the diet during the first 21 d of nursery exhibited a 5.8% better feed conversion (P = 0.02). An interaction between phytase source and dose was observed for average live weight and daily weight gain over the 42-d nursery period (P < 0.05). Supplementing the diet with 2,000 FTU/kg of fungal phytase improved daily weight gain and live weight throughout the experimental period compared to piglets supplemented with 500 FTU/kg of the same phytase source. Additionally, it resulted in better final weights compared to piglets supplemented with 500 FTU/kg of bacterial phytase. Phytase inclusion at 2,000 FTU/kg improved feed conversion by 2.07% over the 42-d nursery period. The most economically favorable feed conversion ratios were observed when supplementing the diet with fungal phytase at 2,000 FTUs/kg.

The study objective was to evaluate dietary limestone buffer inclusion rates for impacting nutrient digestibility and excretion when growing dairy cattle are fed high distiller grains with solubles (DDGS) limit-fed ration. The hypothesis was that feeding more limestone buffer would offset a low rumen pH when feeding a high DDGS inclusion rate. Five ruminally cannulated Holstein and Brown Swiss steers were used in a crossover design having 2-wk periods to evaluate high and low buffer inclusion rates when limit-fed. Treatments were similar in ingredient composition being: 1) 40% DDGS at 0.80% high CaCO₃ buffer inclusion (HIGH) and 2) 40% DDGS with 0.25% low CaCO₃ buffer inclusion (LOW) with the remaining ration consisting of grass hay with minerals and vitamins. Rations were limit-fed at 2.50% of body weight (BW) using Calan feeding doors with steers being weighed every 2 wk with ration amounts adjusted accordingly. Rumen fluid was collected via the ruminal cannula at the start and end of each period for pH, ammonia-n, and volatile fatty acid (VFA)s. Fecal grab samples were collected at the end of each period for measurement of total-tract nutrient digestibility. There were no treatment-by-period interactions (P > 0.10) for any of the growth parameters measured. Gains in frame growth parameters were similar (P > 0.10) for steers fed both rations. BWs and gains were similar (P > 0.10) for steers fed both rations. Steers fed the LOW ration demonstrated a numeric improvement in average daily gain combined with a tendency (P < 0.06) for lower dry matter intake resulting in an improved (P < 0.01) feed efficiency (gain:feed) compared with steers fed the HIGH ration. Steers fed HIGH demonstrated greater (P < 0.01) ruminal ammonia-N and isovalerate concentrations compared with steers fed the LOW buffer ration. Steers fed both buffer inclusion rates were similar (P > 0.10) for ruminal pH and remaining VFAs concentrations. Steers fed both buffer inclusion rates were similar (P > 0.10) in DM and organic matter digestibilities. Limit-feeding a high DDGS inclusion rate ratio combined with a low buffer inclusion rate improved feed efficiency while maintaining growth performance. The study hypothesis was rejected in that feed efficiency can be enhanced when feeding a high DDGS ration by feeding a low calcium carbonate buffer.

The objective of this study was to investigate the effects of body condition score (BCS) of cull cows on carcass characteristics, carcass-cutting yields, profitability, and tenderness development for the longissimus lumborum and psoas major muscles. During a 5-wk period (May-June 2023), 10 boner cull cows (BCS 4 to 6) and 10 leaner cull cows (BCS 1 to 3) were purchased at a commercial auction market. Live conformation, carcass characteristics, weights of fabricated cuts, tenderness, pH decline, and temperature decline were recorded following slaughter. Carcasses were fabricated into the following cuts: knuckle, inside round, outside round, eye of round, strip loin, top sirloin, bottom sirloin flap, tenderloin, flank, ribeye roll, chuck tender, and brisket, whereas lean was separated into lean and fat components. Beef processor returns for boner cows were calculated as the sum of USDA Carlot Report values for the subprimal cuts, trim, bone, and drop value subtracted by actual live costs at the auction market whereas beef processor returns for leaner cows were calculated as the sum of USDA Carlot Report values for the trim, bone, and drop value subtracted by actual live costs at the auction market. Carcass and merchandizing value parameters were analyzed using a completely randomized design with a fixed effect of classification (leaner or boner) and a random effect of slaughter day. Live weight was used as a covariant for all carcass and merchandizing value parameters due to the pronounced effect of live weight for most parameters. Temperature decline, pH decline, shear force, and cooking loss parameters were analyzed using a completely randomized design with a fixed effect of classification (leaner or boner) and a random effect of slaughter day. Boner cows were found to be heavier for both live and carcass weights when compared with leaner cows. In addition, backfat thickness was 0.39 cm greater (P = 0.03), and ribeye area was 9.17 cm² (P = 0.05) greater for boner cows compared with leaner cows. This resulted in boner cows yielding larger subprimal cuts and a greater amount of lean trim, which in turn generated more beef processor revenue. However, specific consideration should be provided for profitability as the ability to market subprimal cuts is highly dependent on muscle size, fat deposition, meat quality, and market prices for both boner and leaner cows.

The cloning of beef carcasses that grade United States Department of Agriculture (USDA) Prime-yield grade (YG) 1 (P1) has produced a sire that ranked well against high-performing bulls from multiple breeds. An F1 (P1 × P1 - first generation offspring) sire would ideally outperform its high-performing parents. A terminal sire study was conducted comparing progeny of an F1 (P1 × P1) sire (AxG1) against progeny (heifers and steers) of four high-performing sires of varying breeds {P1 (ALPHA); Angus; Simmental; Angus × Simmental}. Production traits included morbidity and mortality frequencies, weaning weight, feedlot arrival weight, and days on feed; carcass traits included frequency of abscessed liver and lung health, quality grade and YG parameters, total carcass value (US$), and carcass value per hundredweight (CWT [45.4 kg]; US$). A completely randomized experimental design was used; data were analyzed using a mixed model with a fixed effect of sire and random effects of harvest date, sex, and pen. AxG1 sired heifers had the highest (P < 0.01) marbling score, the highest (P < 0.01) carcass value per CWT, and numerically had the lowest calculated YG and highest frequency of YG one carcass. Steers sired by AxG1 had the least (P = 0.05) backfat, lowest (P < 0.01) calculated YG, highest (P < 0.01) marbling score, highest (P < 0.01) frequency of USDA Prime carcasses, the greatest (P < 0.03) total carcass value, and greatest (P < 0.01) carcass value per CWT. Collectively, AxG1 steer and heifer carcasses exhibited the least 12th rib fat thickness and lowest USDA YG in addition to the largest longissimus muscle area, highest marbling score, and greatest frequency of USDA Prime. These data suggest that AxG1 performed comparably to other high-performing industry terminal sires in carcass quality and YG outcomes.

Formaldehyde has been found to decrease virus concentrations in feed and ingredient matrices. Continued research is needed to identify the appropriate inclusion levels and application time for different viruses in these matrices. The objective was to evaluate different inclusion levels of formaldehyde when applied either pre- or postinoculation of porcine epidemic diarrhea virus (PEDV), type 2 porcine reproductive and respiratory syndrome virus (PRRSV), and Seneca Valley virus 1 (SVV1) to complete feed or soybean meal. The experiment was designed in a 2 × 2 factorial with a formaldehyde-based product (Termin-8, Anitox Corporation, Lawrenceville, GA) applied either before virus inoculation (preinoculation) or after inoculation (postinoculation) at either a 2 or 3 kg/MT. On day 0, samples of the respective matrices were weighed in 50 g aliquots and added to 500 mL bottles. Formaldehyde was applied to the preinoculation samples at the respective inclusion levels and 50 µL of each virus were added to the postinoculation samples. All bottles were shaken and allowed to sit at room temperature for 24 h. On day 1, virus was added to the preinoculation samples and formaldehyde was added to the postinoculation bottles. Half of the samples were immediately processed (0 h) and the other half were incubated at room temperature for an additional 24 h. Samples were processed and aliquots were analyzed via triplex PCR. An application time × inclusion level interaction was observed for PEDV at 0 h and SVV1 and PEDV at 24 h in complete feed, where less viral RNA (P < 0.05) was detected in the postinoculation samples at either inclusion level as compared to the positive controls. In soybean meal, the same interaction was observed in PEDV and PRRSV at 0 h and SVV1 and PEDV at 24 h with less detectable RNA observed (P < 0.05) in the postinoculation samples regardless of inclusion level than the preinoculation counterparts and the controls. Overall, an application time effect was noticed in each matrix where less RNA was detected in the postinoculation samples at 0 h (P < 0.05) compared to the preinoculation samples and the control, and at 24 h, both the pre- and postinoculation samples had less detectable RNA (P < 0.05) than the control. Overall, formaldehyde can reduce detectable RNA immediately in contaminated complete feed and soybean meal, with greater decreases observed as mitigant contact time increases.

The objective of this study was to evaluate differences in the performance of offspring of boars selected with an index emphasizing resilience and boars selected based on a traditional index, emphasizing feed efficiency and carcass quality (traditional) index vs. a customized (resilience) index. The resilience index was identical to the traditional index, except that extra emphasis was placed on piglet vitality (increased by 66%), growth rate (decreased by 14%), and feed intake (increased substantially by 5,157%). Sows were mated to either boars selected based on the resilience index or boars selected on the traditional index. Weaned offspring were vaccinated for Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) and experimentally infected with PRRSV RFLP 1-7-4 four weeks later. Offspring were allocated to pens (n ~ 27 pigs/pen; n = 27 pens/group) by sire-selection group for a total of 1,458 pigs in 54 pens. The weight of each pen was recorded on 0, 42, and 110 d postinfection (DPI) and used to calculate average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR). Mortalities were recorded from 0 to 110 DPI and necropsies were routinely performed to characterize pathogens present within the barn. Pigs classified as full value (i.e., >104 kg and void of defects) were slaughtered and hot carcass weight (HCW), backfat, loin depth, and lean weight were obtained from the slaughter plant. Effects of progeny group on performance, carcass characteristics, and mortality rate were estimated with a mixed linear model. Differences between progeny groups in ADG (P > 0.27), HCW (P = 0.68), backfat (P = 0.13), or loin depth (P = 0.39), and mortality rate (P = 0.29) were not detected. From 0 to 42 DPI, offspring of boars selected based on the resilience index had higher ADFI (0.06 kg/d, P = 0.01) and higher FCR (0.12, P = 0.01). In summary, results from this study do not support selection of boars for increased feed intake, piglet viability, and robustness in order to prevent losses caused by PRRSV, but selection response was only measured after one generation of male selection. The impact of multiple generations of selection, or the development of an index including traits derived from data collected under disease-challenged conditions should be explored. The data collected for this study are a valuable resource to explore additional genetic selection strategies for enhanced resilience to a multifactorial PRRS challenge.