Effects of in ovo injection of nicotinamide riboside on high-yield broiler myogenesis.

The objective of this study was to determine the effects of in ovo injection of high-yield broiler embryos with nicotinamide riboside (NR) on pectoralis major muscle (PMM) development, growth, and gene expression. Fertilized Cobb 700 broiler eggs were randomly assigned to one of four treatments within a 2 × 2 factorial design. Factor 1 consisted of NR dose (DOS) with eggs receiving 0 or 2.5 mM NR. Factor 2 consisted of injection location (LOC), with treatments injected into either the yolk sac or albumen. At day 10 of incubation, 100 µL of the assigned NR dose was injected into the yolk sac of the developing embryo and chicks were euthanized within 24 h of hatching. Chick PMM and individual fiber morphometrics, and expression of genes associated with cell cycle progression were analyzed. There were DOS × LOC interactions for hatched chick PM weight and length (P < 0.04). When NR was injected into the albumen, PMM weight decreased (P < 0.05); when NR was injected into the yolk, PMM weight increased (P < 0.05). Pectoralis major length was not affected (P > 0.05) when NR was injected into the albumen but was increased (P < 0.05) when NR was injected into the yolk. There was a DOS × LOC interaction (P = 0.04) for muscle fiber density and tended to be a DOS × LOC interaction (P = 0.07) for muscle fiber CSA. Pectoralis major muscle fiber density was not affected when NR was injected into the albumen (P > 0.05), but density increased when NR was injected into the yolk (P < 0.05). There were DOS × LOC interactions for hatched chick COXII, cyclin D, and SIRT1 expression (P ≤ 0.04), which may indicate NR improves skeletal muscle development and growth by enhancing myoblast proliferation during embryonic development.

Broiler chicken weight gain is a result of genetics and nutrition, with increased muscle mass attributed to accelerated embryonic myogenesis and posthatch muscle growth. During the avian incubation period, in ovo injection may be used as a strategy to deliver exogenous supplements into growing embryos for improving skeletal muscle development and growth. Nicotinamide riboside (NR), a vitamin B3 analog, is a human performance supplement used to stimulate mitochondria biogenesis and elevate tissue NAD+ levels. Research showed injecting NR into the chick embryonic yolk sac increased breast muscle weight and muscle satellite cell numbers and proliferation rate. Therefore, our objective was to determine the effects of in ovo injection of high-yield broilers with NR on broiler breast muscle development and growth. Our study showed in ovo injection of NR into the yolk sac increased hatched chick breast muscle morphometrics, which coincided with an increase in muscle fiber density and tended to decrease fiber cross-sectional area. Increased Sirtuin1 and cyclin D mRNA expression of hatched chicks from eggs injected with 2.5 mM NR into yolk sac indicate a potential NR regulated Sirtuin1/cyclin D molecular mechanism mediating chicken muscle early development.

Effects of supplementing docosahexaenoic acid-rich microalgae and antioxidants on beef longissimus lumborum steak color stability and sensory characteristics.

The objective of this study was to determine the effects of four microalgae and antioxidant feeding regimens on beef longissimus lumborum color stability and palatability. Steers were blocked by weight and randomly assigned to one of four dietary treatments fed during a 45-d feeding period. Treatments (n = 10 per treatment) consisted of a control diet (CON) and control diet plus 100 g∙steer-1∙d-1 microalgae (ALGAE), ALGAE plus antioxidants (103 IU/d vitamin E and Sel-Plex) fed throughout feeding (AOX), and AOX fed for the final 10 d of finishing (LATE). The longissimus lumborum muscle was removed, aged for 14 d, and fabricated into steaks for objective and subjective color and palatability analyses. There were treatment × day of display interactions for a* value and steak surface metmyoglobin percentage (P < 0.01). There were no treatment differences through day 4 of display for a* value (P > 0.16) and day 5 of display for surface metmyoglobin (P > 0.10). By day 10 of display, ALGAE steaks had a smaller a* value than all other treatments (P < 0.01). Steaks from AOX steers had a greater (P < 0.01) a* value than CON steaks, whereas both a* values did not differ from LATE steaks (P > 0.19). By the end of display, ALGAE steaks had more metmyoglobin than the other treatments (P < 0.01). Steaks from AOX steers had less metmyoglobin than CON and LATE steaks (P < 0.04), which did not differ (P > 0.25). Treatment did not affect trained panel ratings (P > 0.15); however, treatment did affect (P < 0.01) off-flavor intensity. Steaks from ALGAE and AOX steers had greater off-flavor ratings than CON steaks (P < 0.03), but did not differ (P = 0.10). Steaks from LATE steers did not differ in off-flavor ratings from the other treatments (P > 0.07). Use of antioxidants improved color stability of steaks from microalgae fed steers; however, panelists still detected off-flavors.

The effects of maternal dietary supplementation of cholecalciferol (vitamin D3) and 25(OH)D3 on sow and progeny performance.

A total of 69 sows (DNA Line 200 × 400) and their progeny were used to determine if feeding a combination of vitamin D3 and 25(OH)D3 influences neonatal and sow vitamin D status, muscle fiber morphometrics at birth and weaning, and subsequent growth performance. Within 3 d of breeding, sows were allotted to one of three dietary treatments fortified with 1,500 IU/kg vitamin D3 (CON), 500 IU/kg vitamin D3 + 25 µg/kg 25(OH)D3 (DL), or 1,500 IU/kg vitamin D3 + 50 µg/kg 25(OH)D3 (DH). When pigs were sacrificed at birth, there were no treatment effects for all fiber morphometric measures (P > 0.170), except primary fiber number and the ratio of secondary to primary muscle fibers (P < 0.016). Pigs from CON fed sows had fewer primary fibers than pigs from sows fed the DH treatment (P = 0.014), with pigs from sows fed DL treatment not differing from either (P > 0.104). Pigs from CON and DL fed sows had a greater secondary to primary muscle fiber ratio compared to pigs from DH sows (P < 0.022) but did not differ from each other (P = 0.994). There were treatment × time interactions for all sow and pig serum metabolites (P < 0.001). Therefore, treatment means were compared within the time period. At all time periods, sow serum 25(OH)D3 concentrations differed for all treatments with the magnitude of difference largest at weaning (P < 0.011), where serum 25(OH)D3 concentration was always the greatest when sows were fed the DH diet. At birth, piglets from DH fed sows had greater serum 25(OH)D3 concentrations than piglets from sows fed the DL treatment (P = 0.003), with piglets from sows fed CON treatment not differing from either (P > 0.061). At weaning, serum concentrations of 25(OH)D3 in piglets from all sow treatments were different (P < 0.001), with the greatest concentration in piglets from DH sows, followed by CON, and followed by DL. There were no treatment × time interactions for any of the metabolites measured in milk and no treatment or time main effects for 24,25(OH)2D3 concentration (P > 0.068). Colostrum collected within 12 h of parturition contained less (P = 0.001) 25(OH)D3 than milk collected on day 21 of lactation. Regardless of time, concentrations of 25(OH)D3 in milk were different (P < 0.030), with the largest 25(OH)D3 concentration from DH fed sows, followed by DL, and then CON. In conclusion, combining vitamin D3 and 25(OH)D3 in the maternal diet improves the vitamin D status of the dam and progeny and it increases primary muscle fiber number at birth.

Effect of diet type and added copper on growth performance, carcass characteristics, energy digestibility, gut morphology, and mucosal mRNA expression of finishing pigs.

A total of 757 pigs (PIC 337 × 1050; initially 27.6 kg BW) were used in a 117-d experiment to determine the effects of added Cu from tribasic copper chloride and diet type on growth performance, carcass characteristics, energy digestibility, gut morphology, and mucosal mRNA expression of finishing pigs. Pens of pigs were allotted to 1 of 4 dietary treatments, balanced on average pen weight in a randomized complete block design with 26 to 28 pigs per pen and 7 replications per treatment. Treatments were arranged in a 2 × 2 factorial with main effects of diet type, a corn-soybean meal-based diet (corn-soy) or a high by-product diet (by-product) with 30% distillers dried grains with solubles (DDGS) and 15% bakery meal, and added Cu (0 or 150 mg/kg added Cu). There were no Cu × diet type interactions for growth performance. Overall, neither added Cu nor diet type influenced growth performance. However, caloric efficiency was decreased (P = 0.001) for pigs fed the by-product diet compared to the corn-soy diet. Pigs fed the by-product diet had decreased (P < 0.05) carcass yield and carcass G:F) and marginally decreased (P < 0.07) HCW and carcass ADG compared to pigs fed the corn-soy diet. A Cu × diet type interaction (P < 0.05) existed for DM and GE digestibility during the early finishing period as added Cu improved (P < 0.05) digestibility of DM and GE in the corn-soy diet, but not in the by-product diet. During the late finishing period, added Cu marginally increased (P = 0.060) DM and GE digestibility while pigs fed the by-product diet had decreased DM and GE digestibility (P = 0.001) compared to those fed the corn-soy diet. For gut morphology, pigs fed added Cu had decreased crypt depth (P = 0.017) in the distal small intestine compared to those fed no added Cu. Furthermore, relative mRNA expression of intestinal fatty acid binding protein (iFABP) was decreased (P = 0.032) in pigs fed added Cu compared to those fed no added Cu. In summary, adding 150 mg/kg added Cu or including 30% DDGS and 15% bakery meal into a corn-soy diet did not influence growth performance. However, HCW ADG and HCW G:F were reduced in pigs fed the by-product diet compared to the corn-soy diet. Only minor differences in gut morphology or mRNA expression were observed from feeding diets with high levels of Cu or by-products compared to a corn-soy diet.

Inmunidad celular en la patogénesis de la cardiopatía chagásica crónica / Cell-mediated immunity in the pathogenesis of chronic Chagas cardiomyopathy

Resumen La cardiopatía chagásica crónica se presenta en un 30% de las personas infectadas con Trypanosoma cruzi. Aunque el parásito puede ser controlado por la respuesta inmune después de la fase aguda, su detección se hace difícil en la fase crónica a pesar de la persistencia de éste en los tejidos de los individuos infectados. Dado que solo un porcentaje de estos individuos crónicamente infectados desarrolla el daño tisular, se sugiere la existencia de factores asociados que predicen la aparición de la sintomatología crónica: a) la genética del hospedero (moléculas del HLA), cuyo papel aún no se ha dilucidado, b) factores dependientes del parásito cómo la variabilidad de los genotipos (TcI a TcVI), su asociación con tropismo y daño tisular; y c) otros factores como la cantidad del inóculo, la reexposición constante a vectores infectados, las diferentes vías de infección y el estado inmunológico del hospedero. Varias teorías han sido implicadas en el compromiso cardiaco, como la persistencia del T. cruzi en los tejidos, la autoinmunidad inducida y el daño tisular producido por la respuesta inmune. En esta revisión se pretende emitir una hipótesis respecto a la disfunción celular inmune producida por la persistencia parasitaria en los tejidos y su papel en la patogénesis de la enfermedad. Se consideran aspectos como el pronóstico de los pacientes con cardiopatía chagásica llevados a trasplante de corazón por falla cardiaca avanzada comparado con otras causas de falla que conducen a trasplante y la posible organización de los infiltrados inflamatorios en el tejido cardiaco, el cual podría funcionar como un tejido linfoide terciario.

Abstract Chronic Chagas cardiomyopathy is present in 30% of people infected with Trypanosoma cruzi. Even though the parasite can be controlled by immune response after the acute phase, its detection is hard in the chronic phase despite its persistence in the tissues of infected individuals. Since only a fraction of these chronically infected individuals develop tissue damage, the existence of associated predictive factors for appearance of chronic symptoms is suggested: a) host's genetics (HLA molecules) whose role has not yet been clarified; b) parasitedependent factors such as genotype variability (TcI to TcVI), their association with tropism and tissue damage; and c) other factors like the amount of inoculum, the constant reexposure to infected vectors, the different infection routes and the host's immune status. Several theories have been put forward with regard to cardiac compromise, such as T. cruzi persistence in tissues, induce autoimmunity and tissue damage caused by immune response. This review intends to propose a hypothesis on cellular immune dysfunction produced by parasite persistence in tissues and their role in the pathogenesis of the disease. Aspects such as prognosis of patients with Chagas cardiomyopathy who undergo heart transplant due to advanced heart failure are taken into consideration and compared to other failure causes that lead to transplants, and also the possibly organisation of inflammatory infiltrates in heart tissue, which could function as a tertiary lymphoid tissue.