establishment-larval-zebrafish-as-an-animal-model-to-investigate

Establishment of Larval Zebrafish as an Animal Model to Investigate <em>Trypanosoma cruzi</em> Motility <em>In Vivo</em>

Chagas disease is a parasitic infection caused by Trypanosoma cruzi, whose motility is not only important for localization, but also for cellular binding ...

UNIVERSIDAD DE LOS ANDES

The utility and attractiveness of adipose tissue within meat products vary based on species, cut, and consumer preference. In beef, producers are rewarded for producing carcasses with greater visual marbling at the 12th and 13th rib juncture, while pork producers are either not rewarded or penalized for producing carcasses with too much adipose tissue. Some consumers prefer to purchase leaner meat cuts, while other consumers pay premiums to consume products with elevated fat content. While no clear consumer adipose tissue preference standard exists, advances in beef and swine nutrition have enabled producers to target markets that enable them to maximize profits. One niche market that has increased in popularity over the last decade is manipulating the fatty acid profile, specifically increasing omega-3 fatty acid content, of beef and pork products to increase their appeal in a healthy diet. While much research has documented the ability of preharvest diet to alter the fatty acid profile of beef and pork, the same studies have indicated both the color and palatability of these products were negatively affected if preharvest diets were not managed properly. The following review discusses the biology of adipose tissue and lipid accumulation, altering the omega-3 fatty acid profile of beef and pork, negative fresh meat color and palatability associated with these studies, and strategies to mitigate the negative effects of increased omega-3 fatty acid content.

Biology, strategies, and fresh meat consequences of manipulating the fatty acid composition of meat.

The objective of this study was to determine the impact of quality grade and steak location on color stability of semitendinosus (ST) steaks during a 9-d refrigerated study. Twenty-one ST muscles (12 Choice and 9 Select) were purchased from a commercial beef packing plant and fabricated into twelve 2.54-cm thick steaks per muscle. Steaks 1, 6, and 12 were designated for immunohistochemistry while remaining steak locations of proximal (steaks 2 to 4), middle (5 to 8), and distal (9 to 11) were randomly assigned to 0, 4, or 9 d of simulated retail display. Surface color attributes of day-9 steaks were recorded daily by a visual color panel and spectrophotometer. On days 0, 4, and 9 of display, steaks were analyzed for metmyoglobin reducing ability (MRA) and oxygen consumption (OC). Grade × day of display (DOD) interactions were detected for L*, a*, surface oxymyoglobin (OMb) and metmyoglobin (MMb) percentages, and visual panel surface redness and discoloration scores (P ≤ 0.02); however, no Grade × DOD interactions were observed for MRA or OC (P > 0.17). There were location main effect (LOC) × DOD interactions for L*, a*, surface MMb, visual panel surface redness and discoloration, and MRA (P ≤ 0.02). Distal steaks had lower L* values compared with the other locations (P < 0.01), which coincided with steaks being rated visually darker red (P < 0.01). Proximal steaks had greater a* values and had less surface discoloration than middle steaks (P < 0.05), which had an increased percentage of surface MMb (P ≤ 0.04). Distal and proximal steaks had increased MRA compared with middle steaks on days 0 and 4 (P < 0.05), and distal steaks had greater OC than the other locations throughout display (P < 0.01). There were fewer type I fibers at the proximal end with a greater percentage located at the middle and distal ends, and an increased percentage of type IIX fibers at the middle and proximal locations (P ≤ 0.01). Less type IIA fibers were detected at the middle LOC compared with the other two locations (P < 0.10). Larger type I, IIA, and IIX fibers were located at the proximal and middle locations compared with the distal LOC (P < 0.01). ST color and color-stability characteristics were influenced by DOD and LOC, which may partially be explained by differences in fiber types among locations.

Effects of quality grade and intramuscular location on beef semitendinosus muscle fiber characteristics, NADH content, and color stability.

The objective of this study was to determine the effects of the LIPEX finishing diet regimen on pork chop n-3 polyunsaturated fatty acid () content and fresh meat quality. Twenty-eight finishing pigs (PIC 359 × F1 Hermitage/NGT; initial BW 81.5 ± 2.55 kg) were subjected to a 49-d feeding trial. Treatments consisted of a 2 × 2 factorial design with Sex ( = 14 barrows and gilts each) and Diet as main effects. Dietary treatments consisted of a 2-phase standard finishing diet regimen or a 2-phase LIPEX finishing diet regimen (EXL Milling, Lloydminster, SK, Canada). The LIPEX diet regimen added the EXL LIPEX.FA369 additive during phase 1 and the EXL LIPEX.FA369 and XFE Omega-3 Finishing Touch during phase 2. Five-days postmortem, whole boneless pork loins were transported to the Kansas State University Meats Laboratory, aged 14 d, and halved immediately behind the spinalis dorsi. After blooming for 30 min, chops were evaluated for Japanese color score and National Pork Producers Council () color and marbling scores. A 2.54-cm chop was taken immediately anterior to the loin cut and was used for fatty acid and proximate composition analyses. Four 2.54-cm chops were cut from the posterior portion of the loin and were utilized for a 7-d simulated retail display analyses, Warner-Bratzler shear force (), and trained sensory panel. There were no Sex × Diet interactions for all variables measured in the study ( > 0.10). The LIPEX finishing regimen increased chop C18:3n-3, C20:5, and C22:5, which decreased the n-6:n-3 ratio ( < 0.01). There were no Diet effects on pH, Japanese and NPPC color and marbling scores, and proximate composition ( > 0.23). Diet did not affect cook loss, WBSF, and trained sensory panel scores ( > 0.012). There were no 2- or 3-way interactions between Diet, Sex, and Day, or Diet and Sex main effects for L*a* values, surface oxy- and metmyoglobin percentages, or visual panel chop redness and surface discoloration scores ( > 0.14). Feeding the LIPEX finishing diet regimen increased chop n-3 PUFA content without negatively impacting fresh chop palatability or color stability.

The effects of the LIPEX finishing diet regimen on pork quality, fatty acid profile, palatability, and color stability.

The objective of this study was to examine the effect of nicotinamide riboside (NR) on pectoralis major muscle (PM) development and growth. Fertilized Cobb 500 broiler eggs ( = 156; average weight of 70.3 g) were ordered by weight, and within each four egg strata, eggs were randomly assigned to treatments within a 2 × 2 factorial arrangement. Factor 1 consisted of NR treatment with eggs receiving 0 or 250 mM NR. Factor 2 consisted of injection location, with treatments injected into either the yolk sac or albumen. Eggs were incubated at a temperature of 37 °C and a relative humidity of 40 ± 2% for the first 18 d of incubation and humidity was increased to 60 ± 2 °C for the final 3 d. On day 10 of incubation, eggs were injected in their designated location with 100 µL of 0.9% sterile saline containing the assigned NR dose. Chicks were hatched, euthanized, and morphometric measurements of the body and left PM were collected. The left PM was also analyzed for muscle fiber cross-sectional area (CSA) and density. There were no treatment × location or main effects for all body morphometric measurements ( > 0.07), except chest width of chicks from eggs injected in the yolk were wider ( = 0.01) than chicks from eggs injected in the albumen. There were only treatment × location interactions for PM weight and length ( < 0.01). When NR was injected into the albumen, PM weight did not differ ( = 0.09); however, when NR was injected into the yolk sac, PM weight increased ( < 0.01). When NR was injected into both locations, PM length increased ( < 0.01), but increased to a greater extent when NR was injected into the yolk sac. There were treatment main effects for PM width and depth ( < 0.01), with NR injected chicks having PM with greater width and depth. There were no treatment × location or main effects for PM fiber CSA ( > 0.06). There was a treatment × location interaction ( < 0.01) for fiber density. When NR was injected into the albumen, fiber density did not differ ( = 0.09); however, when NR was injected into the yolk sac, fiber density increased ( < 0.01). Injecting NR into the yolk sac of the developing embryo at day 10 of incubation increased PM development which was due to an increase in muscle density.

In ovo feeding of nicotinamide riboside affects broiler pectoralis major muscle development.

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 ( = 10 per treatment) consisted of a control diet (CON) and control diet plus 100 g∙steer∙d 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  value and steak surface metmyoglobin percentage ( < 0.01). There were no treatment differences through day 4 of display for  value ( > 0.16) and day 5 of display for surface metmyoglobin ( > 0.10). By day 10 of display, ALGAE steaks had a smaller  value than all other treatments ( < 0.01). Steaks from AOX steers had a greater ( < 0.01)  value than CON steaks, whereas both  values did not differ from LATE steaks ( > 0.19). By the end of display, ALGAE steaks had more metmyoglobin than the other treatments ( < 0.01). Steaks from AOX steers had less metmyoglobin than CON and LATE steaks ( < 0.04), which did not differ ( > 0.25). Treatment did not affect trained panel ratings ( > 0.15); however, treatment did affect ( < 0.01) off-flavor intensity. Steaks from ALGAE and AOX steers had greater off-flavor ratings than CON steaks ( < 0.03), but did not differ ( = 0.10). Steaks from LATE steers did not differ in off-flavor ratings from the other treatments ( > 0.07). Use of antioxidants improved color stability of steaks from microalgae fed steers; however, panelists still detected off-flavors.

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

Poultry and pork muscle defects and meat quality - consequences, causes, and management.

The objective of this study was to collect and interpret three-axis acceleration, temperature, and relative humidity data from six locations within commercial transport trailers shipping market-weight pigs. Transport was observed in Kansas (n = 15) and North Carolina (n = 20). Prior to loading, three-axis accelerometers were affixed to six locations on the trailers: top fore (TF), top center (TC), top aft (TA), bottom fore (BF), bottom center (BC), and bottom aft (BA) compartments. Data were post-processed to calculate root-mean-square (RMS) accelerations and vibration dose values (VDV) in the vertical direction and the horizontal plane. These values were compared with exposure action values (EAV) and exposure limit values (ELV), vibration levels deemed uncomfortable and potentially dangerous to humans. Additionally, RMS and VDV were compared among the trailer compartments. The vertical RMS accelerations for all compartments exceeded the EAV for loads measured in Kansas, and for the majority of the compartments measured in North Carolina. Many compartments, specifically the BA compartment from all trips, exceeded the vertical ELV. Regardless of where the data were collected, fewer compartments exceeded the EAV in the horizontal orientation. Only BA compartments exceeded the ELV in the horizontal orientation. There were Area × Level interactions for vertical and horizontal RMS and VDV (P < 0.01). The BF compartment had a greater vertical RMS value than the TF, TC, and BC (P < 0.02) compartments, but did not differ (P = 0.06) from the TA compartment. The vertical RMS of the TA compartment did not differ from the TF, TC, and BC compartments (P > 0.13). The BF compartment had a greater (P = 0.02) vertical VDV value than the TC location, but did not differ from the other locations (P > 0.16). All other locations did not differ in vertical VDV (P > 0.12). The BF compartment had greater horizontal RMS than the TC and TA compartments (P < 0.01), but did not differ from TF and BC compartments (P > 0.12). All other compartments did not differ in horizontal RMS (P > 0.34). All compartments, aside from the BA compartment, did not differ in horizontal VDV (P > 0.19). Vibration analyses indicated the BA compartment had the greatest vertical and horizontal vibrations and a large percentage of the compartments exceed the EAV and ELV, which indicated pigs may have experienced uncomfortable trips that could cause discomfort or fatigue.

Measurement of the three-axis vibration, temperature, and relative humidity profiles of commercial transport trailers for pigs.

The objective of this study was to determine the effects of in ovo injection of nicotinamide riboside (NR) on broiler embryonic myogenesis. Fertilized Cobb 500 broiler eggs (N = 240) were sorted by weight and within each strata, randomly assigned to 1 of 4 NR dose treatments (0 mmol, 250 mmol, 500 mmol, or 1 mol; final concentration in yolk of 0, 2.5, 5.0, or 10.0 mmol) of NR. 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. Pectoralis major muscle (PMM) and individual fiber morphometrics were collected. Chicks injected with NR had greater PMM weight and length (P < 0.01), but did not differ from each other (P > 0.14). Chicks from eggs injected with NR had greater PMM weight and width than control chicks (P < 0.01), but did not differ from each other (P = 0.86). Chicks from eggs injected with 500 mmol NR had greater PMM depth than control and 1M chicks (P < 0.04), which did not differ (P = 0.24) from each other. Chicks from eggs injected with 250 mmol NR did not differ in PMM length compared with all other treatments (P > 0.06). There was no treatment effect (P = 0.20) for PMM fiber cross-sectional area; however, there was a treatment effect (P < 0.01) for muscle fiber density. Chicks from eggs injected with 1 mol NR had greater fiber density than all other treatments (P < 0.01). Chicks injected with 250 and 500 mmol NR had greater fiber density than control chicks (P < 0.01), but did not differ (P < 0.06) from each other. Injecting developing embryos at day 10 of incubation increased hatched chick PMM morphometrics, which were partly because of the NR catalyzed increase in muscle fiber density.

The effects of in ovo nicotinamide riboside dose on broiler myogenesis.

The objective of this study was to determine effects of extended aging and intramuscular location on Warner-Bratzler shear force (WBSF), muscle fiber cross-sectional area (CSA), and protein degradation of semitendinosus (ST) and longissimus lumborum (LL) steaks. Left ST and LL were removed from 40 carcasses at 6 d postmortem. The ST was fabricated into 5 locations (LOC), with LOC 1 being most proximal and LOC 5 being most distal. The posterior LL was fabricated into 3 LOC, with LOC 1 being most anterior. Vacuum sealed ST steaks were aged 7, 14, 28, 56, or 112 d postmortem, while LL steaks were aged 7, 28, or 112 d postmortem at 2 ± 1°C. A steak from each LOC was assigned to WBSF or laboratory analyses. There were no Day of Aging (DOA) × LOC interactions for all dependent variables (P > 0.06). There were DOA effects for ST and LL WBSF values and degraded 38-kDa desmin (DES; P < 0.01). Day-7 ST-steak WBSF value was greater than all other days (P < 0.01) and d-14 steaks had greater WBSF value than remaining days (P < 0.05). Day-28 ST-steak WBSF values were greater than d-56 and -112 (P < 0.01), which did not differ (P = 0.53). In the LL, d-7 steaks had greater WBSF values than the other two timepoints (P < 0.01) and d-28 steaks had greater (P < 0.01) WBSF values than d-112 steaks. Degraded ST 38-kDa DES content was less on d 7 and 14 compared to all other days (P < 0.03), but did not differ (P = 0.79) from each other. Days 28 and 56 38-kDa DES content was less than d 112 (P < 0.01), but did not differ (P = 0.34) from each other. Degraded LL 38-kDa DES content was less on d 7 than d 28 and 112 (P < 0.02), which did not differ (P = 0.67). There were LOC effects for only ST WBSF and muscle fiber CSA (P < 0.05). Semitendinosus steak LOC 1 and 2 had greater WBSF values than all other locations (P < 0.01), but did not differ (P = 0.32) from each other. Semitendinosus steak LOC 3 and 5 had greater WBSF values than LOC 4 (P < 0.01), but did not differ (P = 0.85) from each other. The CSA of all ST fiber types were largest in LOC 1 compared to all other fiber types (P < 0.01). The CSA of all LOC 2 and 3 fiber types was greater than LOC 4 and 5 (P < 0.01), but were not different from each other (P > 0.81), and LOC 4 had greater CSA than LOC 5 (P < 0.01). Steak aging WBSF value improvements seemed proteolysis catalyzed, while the ST intramuscular tenderness gradient was more likely due to muscle fiber CSA.

Effects of extended postmortem aging and intramuscular location on protein degradation, muscle fiber morphometrics, and tenderness of beef longissimus lumborum and semitendinosus steaks.

John M. González

Laboratory of Basic Medical Sciences,
School of Medicine,
Laboratory of Basic Medical Sciences, School of Medicine

UNIVERSIDAD DE LOS ANDES

Establishment of Larval Zebrafish as an Animal Model to Investigate Trypanosoma cruzi Motility In Vivo

John M. González

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Laboratory of Basic Medical Sciences,School of Medicine,Laboratory of Basic Medical Sciences, School of Medicine

UNIVERSIDAD DE LOS ANDES

Establishment of Larval Zebrafish as an Animal Model to Investigate Trypanosoma cruzi Motility In Vivo

Laboratory of Basic Medical Sciences,
School of Medicine,
Laboratory of Basic Medical Sciences, School of Medicine