Meta-analysis of the relationship between ractopamine and dietary lysine levels on carcass characteristics in pigs

A meta-analysis was carried out to evaluate the relationship between ractopamine and dietary lysine levels on carcass characteristics in pigs. The database was composed by 29 articles published in international journals from 1990 to 2007, totalizing 155 treatments and 3786 pigs. Average inclusion of ractopamine was 15.3 ppm (ranging from 0 to 30 ppm) and daily average intake of ractopamine was 24.9 mg. Ractopamine addition increased (P < 0.05) hot carcass weight in 4%, loin area in 12% and lean meat content in 4%. Pigs supplemented with ractopamine presented decrease (P < 0.05) of 8% in backfat thickness at the tenth rib, 3% in backfat thickness at the last rib and 5% in mean backfat thickness. Each increase in 1 mg of ractopamine intake represented a reduction of 0.3 mm in tenth-rib (Y = 29.61-0.308 RAC + 0.025 RAC², R² = 0.81, RAC: ractopamine intake expressed in mg) and 0.5 mm at last-rib backfat thickness (Y = 30.52 + 0.519 RAC-0.0054 RAC², R² = 0.94). The use of ractopamine affected (P > 0.05) neither carcass length and dressing, nor meat marbling and color. Loin area was positively correlated (r = 0.27, P < 0.05) and mean backfat thickness was negatively correlated (r = − 0.27, P < 0.05) to dietary lysine concentration. Pigs supplemented with ractopamine whose daily intake of lysine per unit of metabolic weight was more than 195 mg presented (P < 0.05) loin area 4% higher and backfat thickness 10% lower than other animals. Supplemented pigs that received diets with lysine content superior to their calculated amino acid requirement presented weight gain 14% higher, lean meat content 17% higher, leaf fat 34% lower and loin area 6% higher when compared to other supplemented animals. Ractopamine increases lean meat content and reduces backfat thickness in carcass, however, the interaction between additive and nutritional components must be considered in diet formulation.     

Dietary grain source and oil supplement: Feeding behavior and lactational performance of Holstein cows

Effects of grain source and dietary oil supplement on dry matter intake (DMI), feeding, chewing behavior, and production performance of lactating dairy cows were evaluated using eight multiparous Holstein cows (77±22.1 days in milk; mean±SD) in a duplicated 4×4 Latin square design with a 2×2 factorial arrangement of treatments. Experimental diets contained either ground barley or ground corn supplemented with either fish oil or soybean oil at 2% of dietary dry matter (DM). Geometric mean particle size of dietary treatments was 4.1 mm. Dry matter intake tended (P=0.09) to be greater for barley- vs. corn-based diets (23.2 vs. 22.3 kg/d), but was reduced for the fish oil compared to soybean oil supplemented diets (21.1 vs. 24.3 kg/d; P<0.001). This reduction in DMI was attributed to smaller meal size (1.24 vs. 1.55 kg of DM; P=0.004) and slower eating rate (0.082 vs. 0.098 kg of DM/min; P<0.001) for fish oil compared to soybean oil supplemented diets. Main treatment effects interacted (P=0.005) for DMI of particles retained on 19 mm sieve but not for sorting index. Eating rate (0.090 kg of DM/min) was similar between barley- and corn-based diets, however, rumination time was greater for barley- compared to corn-based diets as result of longer rumination bout duration (32.5 vs. 28.5 min/bout; P=0.01). Barley- compared to corn-based diets increased total chewing time by 71 min (709 vs. 638 min) for cows fed fish oil, but not for cows fed soybean oil. Grain source did not affect milk yield or milk composition. Compared to soybean oil, fish oil negatively affected milk yield (40.4 vs. 43.4 kg/d; P=0.01), and thereby, both milk fat (0.91 vs. 1.26 kg/d; P<0.001) and protein (1.23 vs. 1.33 kg/d; P=0.007) production. However, feed efficiency (milk yield/DMI) was greater in fish oil compared to soybean oil supplemented diets (1.94 vs. 1.80; P=0.003). Results indicated that grain source and oil supplement can interact to affect feeding and chewing behavior, but not lactational performance of lactating cows.     

Sunflower-seed oil,rapidly-degradable starch,and adiposity up-regulate leptin gene expression in lactating goats

We conducted experiments to evaluate the effects of lipid supplementation and the nature of starchy concentrate on the regulation of leptin synthesis in lactating goats. Multiparous goats in mid- to late lactation received diets based on different forages and containing plant oil or seeds rich in either 18:1c9, 18:2n-6 or 18:3n-3 corresponding to 3%–7% dry matter (DM) as lipid supplements, or diets based on concentrate as either rapidly or slowly degradable starch. The isoenergetic replacement of a part of the concentrate by either oleic sunflower-seed oil, formaldehyde-treated linseeds, or linseed oil did not modify leptinemia and the leptin mRNA concentration in adipose tissues, suggesting a lack of effect of 18:1c9, 18:3n-3, or their biohydrogenation products. Conversely, leptinemia and the leptin mRNA abundance were increased (by 20% and 140%, respectively, P < 0.05) in goats fed sunflower-seed oil under a grassland hay-based diet but not a maize silage-based diet, at similar energy intakes and adiposity. Thus, 18:2n-6 per se may up-regulate leptin gene expression, but the effect could be blunted by other fatty acids formed during the ruminal digestion of sunflower-seed oil when combined with maize silage. Consumption of rapidly but not slowly degradable starch increased (by 17%, P < 0.05) leptinemia. Moreover, during lactation, plasma leptin was positively correlated (P < 0.05) to adiposity parameters and negatively correlated to fiber intake. The results suggest that leptinemia responds poorly to nutritional factors in lactating goats, thus highlighting the physiological need to sustain hypoleptinemia during lactation.     

Alfalfa polysaccharides improve the growth performance and antioxidant status of heat-stressed rabbits

The study was conducted to evaluate the antioxidant properties of alfalfa polysaccharides (APS) extracted from alfalfa (Medicago sativa L.) through 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging assay and the effects of the inclusion (0%, 0.1%, and 0.5%) of APS in the diet on the growth performance and antioxidant status in heat-stressed rabbits. 120 New Zealand male rabbits (average body weight 1123 g, 40 d old) were divided into three groups (40 rabbits per group) and were fed with a basal diet or the basal diet with 1 g or 5 g of APS/kg of diet. Rabbits had free access to diets and water in an environmentally controlled room at 30 ± 1 °C and 55% relative humidity during the entire period (21 d). On days 7, 14 and 21 of the trial, body weight and feed intake were measured and blood samples were collected for assay of antioxidant induces. Liver tissue samples were collected on day 21 for assay of antioxidant induces. Results in vitro showed the scavenging effect of APS on DPPH radicals increased (P < 0.05) in a dose-dependent manner. The APS exerted an inhibitory effect on DPPH radical generation, with 66.3% inhibition at 100 µg/mL and 74.5% inhibition at 250 µg/mL. Results in vivo showed that APS 0.1% supplementation increased (P < 0.05) average daily gain (ADG) and reduced (P < 0.05) feed conversion rate (FCR) in the first week of trial. Compared with the control group, average daily feed intake (ADFI) was significantly (P < 0.01) reduced by APS treatment. From days 8 to 14 of the trial, ADG of the APS 0.5% group was greater (P < 0.05) than that of the control group. Compared with the control group, FCR was significantly (P < 0.05) reduced by APS treatment. From days 15 to 21 of the trial, ADFI of the APS 0.1% group was greater (P < 0.05) than that of the control group. For the overall period, APS 0.5% supplementation had a significantly (P < 0.05) positive effect on ADG. ADFI and FCR were lower (P < 0.05) with APS than without APS. Furthermore, on day 7, the inclusion of APS reduced significantly MDA (P < 0.01). The rabbits fed with APS 0.1% had significantly (P < 0.01) lower cortisol and greater (P < 0.05) T-AOC, SOD, and GSH-Px than the control group. On day 14, addition of APS increased T-AOC (P < 0.01) and reduced MDA (P < 0.05). The APS 0.5% group showed lower (P < 0.05) cortisol and greater (P < 0.05) GSH-Px than the control group. On day 21, the rabbits fed with the APS 0.5% diet had greater (P < 0.05) GSH-Px and T-AOC compared with the control rabbits. In contrast, the opposite was true for cortisol (P < 0.05) and MDA (P < 0.05). On day 21, MDA was lower (P < 0.01) with APS than without APS in the liver tissue. Hepatic GSH-Px activity of rabbits fed with the APS 0.5% diet was greater (P < 0.05) than those of other groups. APS supplementation seemed to have a positive influence on the growth performance and antioxidant status of heat-stressed rabbits.     

Effects of dietary inclusion of yerba mate (Ilex paraguariensis) extract on lamb muscle metabolomics and physicochemical properties in meat

This study aimed to evaluate the effect of dietary yerba mate (Ilex paraguariensis) extract (YME) on muscle metabolomics and physicochemical properties of lamb meat. Thirty-six uncastrated male lambs (90 d old) were fed experimental diets, which treatments consisted of 0%, 1%, 2%, and 4% inclusion of YME. Animals were fed for 50 d before slaughter. Muscle and meat samples were collected for metabolomics and meat quality analysis, respectively. The experiment was carried out in a randomized block design and analyzed using orthogonal contrasts. There was a quadratic effect of YME inclusion in tenderness (P < 0.05) and a positive linear effect on meat lightness (P < 0.05). No qualitative changes (P > 0.05) on individual metabolites were observed; however, changes in the quantitative metabolic profile were observed, showing that animals fed 1% and 2% of YME have a greater concentration of desirable endogenous muscle antioxidants, with direct impact on metabolic pathways related to beta-alanine metabolism and glutathione metabolism. Therefore, YME dietary supplementation up to 2% of the diet to lambs had little to no effects on the majority of meat quality traits evaluated; moreover, 4% of YME inclusion negatively affected feed intake and meat quality traits.     

Growth performance,apparent nutrient digestibility,caecal fermentation,ileal morphology and caecal microflora of growing rabbits fed diets containing probiotics and prebiotics

Ninety eight male, mixed breed weaner rabbits were used in a 70 day feeding trial to study the performance, apparent nutrient digestibility, caecal fermentation, ileal morphology and caecal microflora of growing rabbits fed diets containing Prediococcus acidilactis (1×10¹⁰ cfu/g; 0.5 g/kg), Bacillus cereus (1×10⁹ cfu/g; 0.5 g/kg), mannan oligosaccharides (MOS; 1 g/kg), arabinoxylans oligosaccharides (AX; 1 g/kg), oxytetracycline (1 g/kg), or synbiotics (TGI; 1 g/kg). A basal diet containing no feed additive was formulated. There were 14 rabbits per treatment. Rabbits fed diets containing MOS had the highest (P<0.05) final live weight and weight gain. Dietary inclusion of prebiotics (MOS, AX) resulted in higher (P<0.05) weight gains and improved feed to gain ratios. Rabbits fed diets containing MOS showed the highest (P<0.05) while those fed diets containing probiotics (Prediococcus acidilactis, Bacillus cereus) had the least (P<0.05) caecal total volatile fatty acid (VFA) concentration. Rabbits fed diets containing prebiotics (MOS, AX) had longer ileal villi than groups fed with other treatments (P<0.05). Inclusion of various additives showed reduced caecal coliform counts. The lowest (P<0.05) lactobacillus count was obtained in the caecal content of rabbits fed diets containing MOS. Poor growth response was obtained with rabbits fed diets containing Prediococcus acidilactis or Bacillus cereus while inclusion of prebiotics in growing rabbits resulted in improved growth and gut morphology. Rabbits fed diet containing MOS showed the highest overall final live weight, weight gain, total VFA concentration and reduced caecal lactobacillus count.     

Clinically relevant multidrug resistant Salmonella enterica in swine and meat handlers at the abattoir

The presence of multidrug resistant (MDR) Salmonella serotypes in slaughtered swine, carcasses, meat and meat handlers is scarcely evaluated. Recently we demonstrated that diverse Salmonella serotypes are frequently present in swine, pork meat and carcasses, and meat handlers at Portuguese abattoirs. Here we have characterized their antibiotic resistance phenotypes and genotypes, helping elucidate the flow of MDR Salmonella in the food chain. Testing 60 Salmonella isolates from different serotypes, the highest frequencies of resistance were observed for tetracycline (T) [70% (n = 42/60), tet(A)/tet(B)/tet(G)], streptomycin (S) [63% (n = 38/60), aadA2/strA/strB], sulfamethoxazole (Sul) [62% (n = 37/60), sul1/sul2/sul3] and ampicillin (A) [57% (n = 34/60), bla_PSE-1/bla_TEM]. Thirty-seven percent (n = 22/60) carried class 1 integrons and multidrug resistance was frequently observed (63% n = 38/60), including those serotypes common to human infections [S. Typhimurium 78% n = 25/32; S. 4,[5],12:i:- 67% n = 2/3; S. Rissen 75% (n = 3/4); S. London 67% n = 2/3; S. Derby 55%; n = 6/11)]. The emergent S. 4,[5],12:i:- isolates were mostly characterized by ASSuT phenotype [bla_TEM/strA-strB/sul2/tet(B)], typical of the European clone, while for the first time the ST phenotype [strA-strB-tet(A)-tet(B)] was also observed. Moreover, we report a first finding of a MDR phenotype in S. London [ANSSuT; bla_TEM-strA-strB-sul2-tet(A)]. Our findings suggest that the abattoir environment and the slaughter operations seem not only to harbor MDR serotypes that originated in the pig reservoir, but also propagate them through cross-contamination processes, involving meat handlers. The present study suggests a probable relationship between swine and human salmonellosis throughout the food chain, which is of interest for epidemiological, animal health and public health purposes.     

Protein digestive dynamics of meat and bone meals in broiler chickens

This study determined the variations in protein digestibilities and digestion rates in broiler chickens offered diets containing 7 different meat and bone meals (MBM). A total of 252 male Ross 308 broiler chickens were offered 7 atypical diets largely based on maize and MBM from 24 to 28 d post-hatch. Each experimental diet was offered to 6 replicates with 6 birds per replicate cage. Excreta were collected in their entirety from 25 to 27 d post-hatch and on 28 d post-hatch. Digesta samples were collected from the proximal jejunum, distal jejunum, proximal ileum and distal ileum. Apparent digestibilities of protein were determined in each segment and apparent digestibilities of amino acids were measured in the distal ileum. There were significant differences in apparent protein digestibility coefficients in the proximal jejunum (P = 0.006), where broiler chickens offered the high ash beef meal (diet 7) generated the lowest protein digestibility in the proximal jejunum (0.318). Similarly, there were significant differences in apparent digestibility coefficients in the distal jejunum (P < 0.001) and distal ileum (P < 0.001) but not in the proximal ileum. More pronounced differences were found in the disappearance rate of protein and there were significant differences in all 4 segments of the small intestine (P < 0.001). Broiler chickens offered the high ash beef meal had the lowest protein disappearance rate (P < 0.001). No difference was observed in the predicted protein digestion rate (P = 0.486) but chickens offered the high ash beef meal had the lowest potential digestible protein (0.662, P = 0.034) whereas the highest potential digestible protein (0.739) was detected in diet 5 (containing a beef meal). This study contributed to the establishment of a preliminary database to include digestion rates of starch and protein into practical diet formulation.     

Effects of dibutyryl cAMP on growth performance and carcass traits in finishing pigs

This study was designed to investigate the effects of dietary supplementation with N⁶, 2′-O-dibutyryl adenosine 3′,5′-cyclic monophosphate (dbcAMP) on growth performance, carcass traits, histochemical characteristics and serum constituents in finishing pigs. Seventy-two Duroc × (Landrace × Large White) barrows (57.3 ± 0.6 kg) were randomly allotted to 3 treatments with 6 replicate pens/treatment (4 pigs/pen). The pigs were fed diets containing 0, 10 and 20 mg dbcAMP/kg, respectively, until the final slaughter weight of approximately 90 kg. There were no differences in growth performance among dietary treatments. Leaf fat proportion and first rib backfat thickness were reduced (P < 0.05), whereas tenth rib backfat thickness tended to decrease (P = 0.10), in pigs fed 10 mg dbcAMP/kg. Lean percentage was greater (P < 0.05) and longissimus muscle area tended to increase (P = 0.10) in pigs fed 10 mg dbcAMP/kg when compared to the control group, but hot carcass weight was not affected by dbcAMP. Growth rate of fat-free lean tissues tended to increase (P = 0.09) in dbcAMP-supplemented pigs. Dietary dbcAMP decreased (P < 0.05) adipocytes diameter in subcutaneous fat, whereas longissimus muscle fiber diameter tended to increase (P = 0.06) with dbcAMP supplementation; however, no difference in longissimus muscle cell density was detected among treatments. Serum concentrations of total protein and 3′,5′-cyclic adenosine monophosphate increased (P < 0.05) in response to dbcAMP, but concentrations of triglycerides, total cholesterol, glucose and urea in serum did not differ among dietary treatments. These results indicate that dbcAMP had a positive effect on carcass traits. Addition of 10 mg dbcAMP/kg to the diet was beneficial for growth performance and lean percentage, as well as improving protein and fat metabolism.     

High levels of whole raw soybean in diets for Nellore bulls in feedlot: effect on growth performance,carcass traits and meat quality

The objective of this study was to evaluate the effect of whole raw soybean (WRS) in the finishing diet of Nellore cattle on productive performance, carcass traits, meat quality, fatty acid profile of meat, and blood parameters. In a completely randomized design, 52 Nellore bulls (mean body weight ± SD: 380 ± 34 kg) were allotted for 84 days. The animals received the following diets with a forage: concentrate ratio of 40/60: (i) WRS0: control diet without soybean grains; (ii) WRS8: diet containing 8% WRS in dry matter basis; (iii) WRS16: diet containing 16% WRS, and (iv) WRS24: diet containing 24% WRS. At intervals of 28 days, the animals were weighed, muscle and adipose tissue was analysed by ultrasound, and blood samples were collected. The animals were slaughtered on day 85 and liver weight and hot carcass weight were measured during slaughter. The pH and carcass dressing were calculated at 24 h after slaughter. Longissimus dorsi muscle samples were collected for the determination of fatty acid profile of meat, ether extract, tenderness and sensory analysis of meat aged for 14 days. Blood cholesterol content increased linearly with increasing proportion of whole raw soybean grains. The diet did not affect performance or carcass attributes. The WRS8 had the highest shear force values. In fatty acid profile, C14:0 decreased (p = 0.05), whereas 16:1, 20:0 and 20:1 fatty acids increased linearly with increasing proportion of WRS (p < 0.05). However, concentration of conjugated linoleic acid cis 9, trans 11 and 17:0 increased with WRS24 and WRS16. In the sensory analysis, WRS24 was more tender with respect to the other treatments (p < 0.05). Finally, the inclusion of WRS in the finishing diet of feedlot Nellore bulls only evidenced little changes in fatty acid profile and tenderness, in animals fed diets containing 16 or 24% soybean.     

Use of 2-hydroxy-4-(methylthio)-butanoic acid to inhibit Salmonella and Listeria in raw meat for feline diets and palatability in domestic cats

While the raw pet food market continues to grow, the risk of bacterial contamination in these types of diets is a major concern, with Salmonella enterica and Listeria monocytogenes being the most frequently associated pathogens in raw pet food product recalls. dl-Methionine is included in some commercial feline kibble and canned diets to improve protein quality; however, an alternative to this is a liquid methionine supplement, 2-hydroxy-4-(methylthio)-butanoic acid (HMTBa), which is also an organic acid. 2-Hydroxy-4-(methylthio)-butanoic acid has previously demonstrated similar efficacy to formic acid against pathogens in a liquid environment and may be a good candidate to inhibit S. enterica and L. monocytogenes in raw ground meat. First, the minimum inhibitory concentration and minimum bactericidal concentration of HMTBa against these pathogens under laboratory growth conditions were determined by measuring growth of pathogens over 36 h when exposed to 10 concentrations of HMTBa (0.10% to 1.00%) mixed with tryptic soy broth. 2-Hydroxy-4-(methylthio)-butanoic acid included at ≥0.50% was bactericidal to S. enterica and L. monocytogenes (P < 0.05). Next, five levels of HMTBa (0.50% to 1.25%) were included in raw ground meat mixtures inoculated with cocktails of S. enterica or L. monocytogenes, and contamination levels were determined at four timepoints: immediately, and after refrigerated storage (4 °C) at 24, 48, and 72 h after removal from freezer (24 h at −20 °C). 2-Hydroxy-4-(methylthio)-butanoic acid included as 1.25% of the meat mixture reduced S. enterica and L. monocytogenes compared with the control (P < 0.05); however, it did not result in total kill of either of these pathogens. Following this, feeding behaviors of seven domestic cats were assessed when offered a raw chicken diet treated with or without 1.25% HMTBa for 5 d each, after which a 2-d 2-choice preference test was conducted. Cats demonstrated a preference for raw diets without HMTBa, but still readily consumed diets with 1.25% HMTBa, suggesting that such a diet was still palatable to them.     

Effect of a dietary supplementation with linseed oil and selenium to growing rabbits on their productive performances,carcass traits and fresh and cooked meat quality

The present experiment tested a dietary supplementation with linseed oil and selenium to growing rabbits. The basal diet (B) contained 3% sunflower oil, while it was substituted with 3% linseed oil in the experimental feed (S). The selenium (Se) content of the two diets was 0.10 vs. 0.46 mg/kg. Rabbits were fed with B diet from the age of 18 days. One group was fed with the B diet until 11 weeks of age (group B), whereas the experimental groups were fed with S diet for 1, 2, 3 or 4 weeks (groups S1, S2, S3 and S4, respectively), before slaughtering (11 weeks of age). Live performance and carcass traits of rabbits, fatty acid (FA) profile and selenium content of their hind leg (HL) and Longissimus thoracis et lumborum (LTL) meat were considered in this study. In addition, the effect of two different cooking methods on the nutritional value of the enriched HL meat was also assessed. The tested dietary supplementation only minimally affected the live performance and carcass traits of rabbits. The S supplementation significantly reduced the Σ n‐6 FA and increased the Σ n‐3 FA of the HL meat and LTL meat, compared to the B diet (p < 0.001); thus, n‐6/n‐3 ratio was improved (p < 0.001). In addition, HL meat and LTL meat of S fed rabbits were significantly enriched in Se reaching a twofold increase in both meat cuts (p < 0.01). Therefore, the S supplementation improved the functional value of the rabbit meat. The heat treatment affected cooking loss, Se and vitamin E contents as well as the oxidative status of the HL meat (p < 0.001), with the different cooking methods providing different results. In addition, even if the beneficial C20:5 n‐3 and C22:6 n‐3 decreased with cooking, the n‐6/n‐3 ratio remained unaffected.     

Inflammation-associated responses in piglets induced with post-weaning colibacillosis are influenced by dietary protein level

Forty piglets (average body weight = 5.32 kg) were used to investigate the effect of dietary crude protein (CP) content on immunological responses following a challenge with enterotoxigenic Escherichia coli (ETEC) K88. Pigs, housed 4 per pen, were randomly allotted to 2 diets: 1) a high, 225 g/kg CP diet (HCP) or 2) a low, 176 g/kg CP diet (LCP) supplemented with crystalline amino acids. Pigs were orally challenged with 6 mL of an ETEC K88 suspension containing 10¹⁰ cfu/mL on d 8 after weaning. Blood samples were collected from 10 pigs (1 pig/pen) on d 7 (at weaning), −24 h, 8 h, 72 h and 7 d after the challenge for determination of plasma urea N (PUN) and serum concentrations of tumor necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β) and haptoglobin (Hp). Tumor necrosis factor alpha, IL-1β and Hp were measured as indicators of inflammatory responses. The concentrations of serum TNF-α at 8 h, 72 h and 7 d after challenge were similar to the level observed at 24 h before challenge but higher (P < 0.05) than the weaning level. Pigs fed the LCP diet had lower (P = 0.032) concentrations of IL-1β (72 vs. 116 pg/mL) at 8 h post-challenge compared with those fed the HCP diet. Likewise, pigs fed the LCP diet tended to have lower (P = 0.088) concentration of Hp (9 vs. 25 mg/dL) compared with those fed the HCP diet at 8 h post-challenge. Compared with the weaning concentration, PUN concentration at 72 h after ETEC challenge was higher (P < 0.05) in pigs fed the HCP diet. The results indicate that the LCP diet supplemented with crystalline amino acids reduced inflammatory responses, as indicated by serum IL-1β, in piglets infected with ETEC K88.     

The relationship of various muscular and skeletal scores and ultrasound measurements in the live animal,and carcass classification scores with carcass composition and value of bulls

The relationships of live animal muscular and skeletal scores and ultrasound measurements and carcass conformation and fat scores with carcass composition and value were determined using 74 bulls. The animals consisted of 53 late-maturing breed crosses and 21 Holstein–Friesian slaughtered at 13 to 17 months of age. They were offered concentrates ad-libitum and 1 kg of grass silage dry matter per head daily for the final 139 day finishing period. Live animal muscular and skeletal scores and ultrasonic muscle and fat depth measurements of the M. longissimus dorsi were recorded at 8 to 12 months of age and pre-slaughter. Following slaughter, carcasses were classified for conformation and fatness and the right side of each carcass was dissected into meat, fat and bone. Carcass conformation and fat scores, (scale 1 to 15) ranged from 4.7 to 14.4 and 2.7 to 11.5, respectively. Pre-slaughter muscular scores showed significant positive correlations with kill-out proportion (r = 0.82), carcass meat proportion (r = 0.72), conformation score (r = 0.94), carcass value (r = 0.72), and the proportion of high-value meat cuts in the carcass (r = 0.49), and significant negative correlations with carcass bone (r = − 0.89) and fat (r = − 0.32) proportions. The associations between pre-slaughter muscular scores and proportion of high-value cuts in meat, perinephric plus retroperitoneal fat and fat score were not significant. Corresponding correlations with muscular scores at 8 to 12 months of age were generally lower than those recorded pre-slaughter. Correlations of ultrasound muscle depth with carcass traits showed similar trends but lower values to those obtained using the muscular scoring procedure. Ultrasound fat depth pre-slaughter was positively correlated with carcass fat proportion (r = 0.56) and fat score (r = 0.54), and negatively correlated with carcass meat proportion, proportion of high-value cuts and carcass value. Correlations with other carcass traits were not significant. Correlations of live animal skeletal scores with carcass traits were generally non-significant. A one unit (scale 1–15) increase in carcass conformation score was associated with significant increases in kill-out proportion, meat yield and carcass value of 11.9 g/kg, 11.9 g/kg and 5.8 cent/kg, respectively. Corresponding effects for a one unit change in fat score were − 2.9 g/kg, − 11.1 g/kg and − 4.9 c/kg. In conclusion, live animal muscular scores and ultrasound measurements and carcass conformation and fat scores were shown to be useful predictors of carcass composition and value.     

Impact of combined α-galactosidase and xylanase enzymes on growth performance,nutrients digestibility,chyme viscosity,and enzymes activity of broilers fed corn–soybean diets

Two experiments were conducted to investigate the effects of a combined α-galactosidase and xylanase preparation on nutrients digestibility and growth performance in broiler chickens. Experiment 1 had 240 broilers allocated to 3 treatments with the dietary supplementation of 0, 300, and 500 g/t of the enzyme combination. Diet and amino acid (AA) digestibility were assessed. Experiment 2 was a 2 × 3 (enzyme × diet) factorial arrangement with 10 replicates of 12 male broilers per replicate. Diets were based on corn–soybean meal (SBM) diet and had 3 nutritional levels (normal, 2% apparent metabolizable energy (AME) and crude protein (CP) reduction, and 4% AME and CP reduction). Each of these diets was fed with or without enzyme supplementation. Growth performance, chyme viscosity, nutrients digestibility, and endogenous enzymes activity were assessed. In experiment 1, enzyme supplementation improved the digestibility of Ca (P = 0.025) and ileal digestibility of total AA, Pro, Alu, Ile, Lys, His, Thr, Glu, Val, Leu, Tyr, and Phe (P < 0.05), and also tended to increase the AME of diets (P < 0.10). In experiment 2, broilers fed the corn–SBM diet with 4% nutrient reduction had better growth performance (P < 0.05), jejunal digesta viscosity at 42 d (P < 0.01), and lower digestibility of gross energy (GE; P < 0.05) when compared with those fed the normal nutrient diet. Enzyme inclusion increased digestibility of CP (P = 0.044), GE (P = 0.009), raffinose (P < 0.001) and stachyose (P < 0.001), improved average daily gain (P = 0.031), and reduced jejunal digesta viscosity at 42 d (P = 0.011). Besides, similar improvements trend in amylase, trypsin, sucrase, and maltase activity with enzyme inclusion were observed as with energy. These data support that the enzyme supplementation increased nutrients and ileal AA digestibility, improved performance and endogenous enzymes activity.     

Effects of high fat,modified wet,corn distiller's grains plus solubles on beef steer performance and carcass characteristics

Corn distiller's grains plus solubles (DGS) have become a common replacement for shelled corn in diets of finishing steers. Numerous studies have evaluated DGS inclusion, both wet (WDGS) and dry (DDGS), into feedlot diets with conflicting reports on feedlot performance and subsequent meat quality. Many authors have failed to describe the nutrient composition of the DGS utilized in their studies making it difficult to determine why different studies have different results. The objective of this study was to evaluate the feedlot performance and subsequent meat quality characteristics of steers fed high fat (10.36±0.72%), modified wet corn distiller's grains plus solubles (HWDGS) at 0, 25, 40, and 70% of the diet dry matter (DM). Angus cross steers (n=240; 335±55 kg) were blocked by source and stratified within block (3 blocks) by body weight (BW) to 32 treatment pens containing either 6 or 10 steers/pen. Pens within block were randomly assigned to one of four diets containing 15% corn silage: (1) 76.9% shelled corn, 6.4% soybean meal 1.5% limestone, 0.2% premix (0 HWDGS); (2) 25.0% HWDGS, 58.20% shelled corn 1.6% limestone, 0.2% premix (25 HWDGS); (3) 40.0% HWDGS, 42.74% shelled corn 2.06% limestone, 0.2% premix (40 HWDGS); (4) 70.0% HWDGS, 12.30% shelled corn 2.5% limestone, 0.2% premix (70 HWDGS). Target BW at harvest was 591 kg±23 kg with 121 steers harvested on day (d) 161 and 117 steers on d 224. Hot carcass weight and liver abscess scores were recorded on d of harvest. Longissimus muscle area, rib fat thickness, marbling score, and kidney, pelvic and heart fat were measured after a 24 h chill. No significant differences were observed between treatments regarding average daily gain (ADG) or BW. Steers fed 0 HWDGS had significantly lower average daily feed intake (ADFI) than steers fed HWDGS and the response was quadratic at lower ADFI. Steers fed 70 HWDGS had lower (P<0.05) dry matter intake (DMI) compared to steers fed lower HWDGS concentrations. Steer gain to feed ratio (G:F) was significantly higher for steers fed 70 HWDGS compared to 0, 25, or 40 HWDGS with a quadratic response at higher % HWDGS diets. Mean United States Department of Agriculture (USDA) quality grade was average choice. Mean USDA yield grade was 3.0. Steers fed 70 HWDGS had significantly smaller rib eye areas and a linear trend (P=0.08) to have lower USDA quality grades compared to steers fed lower HWDGS inclusion rates. Increasing dietary HWDGS increased polyunsaturated fatty acid (PUFA) and PUFA/saturated fatty acid concentrations in intramuscular fat with both a linear and quadratic effect. High fat modified WDGS can be fed up to 70% of diet DM without compromising feedlot performance, carcass characteristics, or meat quality.     

Effectiveness of maifanite in reducing the detrimental effects of aflatoxin B1 on hematology,aflatoxin B1 residues,and antioxidant enzymes activities of weanling piglets

A feeding trial was conducted to evaluate the effectiveness of maifanite, which is mainly composed of aluminosilicate, in reducing the adverse effects of aflatoxin B₁ (AFB₁) on hematology, AFB₁ residues, and antioxidant enzymes activities in weaning piglets. A total of 32 (9.28±0.17 kg BW) individually housed crossbred piglets (Duroc×Landrace×Large white) were randomly allotted to 1 of 4 dietary treatments in a 2×2 factorial arrangement with 8 replicates per treatment. The dietary treatments included 2 AFB₁ levels (5.3 and 372.8 μg/kg) and 2 maifanite levels (0% and 1%). No differences in average daily gain, average daily feed intake, and gain to feed ratio were observed among treatments. Ingestion of the AFB₁-contaminated (AF) diets (372.8 μg/kg of AFB₁) reduced (P<0.05) the numbers of neutrophil, monocyte, and total leukocyte. There were no effects of AFB₁ on gamma glutamyltransferase, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase activities, and total protein, albumin, urea N, total bilirubin, IgG, IgA, and IgM concentrations in serum. Aflatoxin B₁ was found in the liver and kidney of piglets fed the AF diets. Piglets fed the AF diets reduced (P<0.05) the total superoxide dismutase, glutathione peroxidase, and catalase activities in serum. However, total superoxide dismutase activity in the liver was increased (P<0.05) in piglets fed the AF diets compared with those fed the basal diets (5.3 μg/kg of AFB₁). There was an interaction (P=0.003) in erythrocyte, but piglets fed the diets containing maifanite had greater erythrocyte and lymphocyte (P=0.035) numbers than those fed the diets without maifanite. The AFB₁ levels in the liver and kidney of piglets fed the AF diet containing maifanite were 29.6% and 41.2% lower, respectively, than those of piglets fed the AF diet alone. Although there was an interaction (P=0.011), piglets fed the diets containing AFB₁ and maifanite had greater serum T-SOD activity compared with those fed the diets with no maifanite. In conclusion, the addition of maifanite to the AF diet resulted in partial restoration of hematology and antioxidant enzymes activities and reduced AFB₁ levels in the liver and kidney.     

Impacts of different spices on in vitro rumen dry matter disappearance,fermentation and methane of wheat or ryegrass hay based substrates

Two completely randomised experiments compared the impact of different spices, each at 30 mg/g substrate DM, on the in vitro dry matter disappearance (IVDMD), methane, ammonia and volatile fatty acids (VFA) from either wheat flour (wheat) (experiment 1) as highly or hay based mixtures (experiment 2) as moderately fermentable substrates. Experiment 1 tested the effects of adding cinnamon, clove, coriander, cumin and turmeric, individually, on the rumen fermentation during their in vitro incubations with wheat for 24 h. All spices reduced methane (P < 0.05) from wheat as compared to the spice-free wheat (control). Coriander reduced methane more followed by turmeric, cumin and cinnamon than the control. The IVDMD of wheat did not differ for most spices except cinnamon where IVDMD was reduced (P < 0.05) as compared to the control. Whilst, rumen ammonia was greatest for cumin (P < 0.01) followed by coriander and turmeric, it was lowest for clove (P < 0.01). The spices did not affect the pH and total VFA of rumen fluid for wheat. However, the presence of clove reduced acetic acid (P < 0.05). Experiment 2 tested the effect of only three (coriander, cumin and turmeric) spices individually or together on the in vitro fermentation of hay based mixtures during 96 h of incubation. Whilst all the individual spices or their mixture reduced methane from the hay based mixtures (P < 0.05), the extent of this reduction was highest for turmeric, second highest for coriander and lowest for cumin. It appeared that most spices modified methane emission from wheat as a single ingredient or hay based mixtures without having detrimental effect on diet disappearance or fermentation in vitro. However, the extent of this modification depended on the type of a spice and substrate. Therefore, careful selection of a spice to suit specific feeds would be essential before their in vivo use to modify the fermentation efficiency of ruminant diets.     

Effect of phytase on phosphorous balance in 20-kg barrows fed low or adequate phosphorous diets

The effects of phytase on phosphorus (P) digestibility are well established. However, there are few studies that report P balance, particularly when phytase is used in diets that have adequate or deficient P. The main objective of the study was to determine the effect of dietary P levels and exogenous phytase on P balance in growing pigs. The first part of the experiment was a 14-d metabolism study conducted with 80 barrows (initial body weight 18.5 ± 0.5 kg) with a 2 × 5 factorial arrangement of treatments and main effects of available P (0.13% available P, low P [Low-P] diet; 0.35% available P, adequate P [Adeq-P] diet) and phytase (0, 250, 500, 2,500, and 12,500 U/kg). A portion of the pigs (n = 24) fed the Low-P diet, with 0, 500, 2,500, 12,500 U/kg phytase, and those fed the Adeq-P diet, with 0 and 12,500 U/kg phytase, remained on test diets for another 4 d, and tissues were collected for determination of bone characteristics and tissue P concentration. There was a P × phytase interaction for P retention that was accounted for by a lack of response to phytase in pigs fed the Adeq-P diet. Retention of P was greater with incremental levels of phytase in pigs fed Low-P diets as compared to those fed Adeq-P diets (P level × phytase, P < 0.01), but calcium (Ca) retention was greater in pigs fed Adeq-P diets (P level × phytase P < 0.01). Apparent total tract digestibility (ATTD) of P was improved by phytase (P < 0.001) and was greater in pigs fed Adeq-P diets as compared to those fed Low-P diets (P = 0.006). Metatarsal bone ash (quadratic, P = 0.01) and strength (linear, P = 0.03) was increased by phytase addition to the Low-P diets. There were no phytase or dietary P effects on P concentrations of the heart, kidney, liver, muscle, and spleen. These results suggest that as compared to the effects in an Adeq-P diet, adding phytase to a Low-P diet was more effective at reducing the P and Ca excretion and restoring average daily gain (ADG). The P released by phytase is absorbed and contributes to improved bone growth, greater rates of tissue accretion, and increased body weight, but does not change tissue P concentrations. There is, however, a threshold for P retention, beyond which it is excreted in the urine.