Growth Rate Of Animals Research Articles

Approaches for testing hypotheses for the hypometric scaling of aerobic metabolic rate in animals.

Hypometric scaling of aerobic metabolism [larger organisms have lower mass-specific metabolic rates (MR/g)] is nearly universal for interspecific comparisons among animals, yet we lack an agreed upon explanation for this pattern. If physiological constraints on the function of larger animals occur and limit MR/g, these should be observable as direct constraints on animals of extant species and/or as evolved responses to compensate for the proposed constraint. There is evidence for direct constraints and compensatory responses to O2 supply constraint in skin-breathing animals, but not in vertebrates with gas-exchange organs. The duration of food retention in the gut is longer for larger birds and mammals, consistent with a direct constraint on nutrient uptake across the gut wall, but there is little evidence for evolving compensatory responses to gut transport constraints in larger animals. Larger placental mammals (but not marsupials or birds) show evidence of greater challenges with heat dissipation, but there is little evidence for compensatory adaptations to enhance heat loss in larger endotherms, suggesting that metabolic rate (MR) more generally balances heat loss for thermoregulation in endotherms. Size-dependent patterns in many molecular, physiological, and morphological properties are consistent with size-dependent natural selection, such as stronger selection for neurolocomotor performance and growth rate in smaller animals and stronger selection for safety and longevity in larger animals. Hypometric scaling of MR very likely arises from different mechanisms in different taxa and conditions, consistent with the diversity of scaling slopes for MR.

Impacts of climate change on Livestock production and productivity and different adaptation strategies in Ethiopia

This review work was conducted to explore the likely impacts of climate change on livestock production and productivity and different adaptation strategies in Ethiopia. National average temperature has increased by 10 c since the 1960s. Most of the livestock owners in the country perceive there is a climate change impacts on Livestock production and productivity. The major effects of climate change on livestock production include feed shortage, shortage of water, livestock genetic resources loss, reduced productivity, and decreased mature weight and/or longer time to reach mature weight in their order of importance. Higher temperatures resulting from climate change may increase the rate of development of certain pathogens or parasites that have one or more life cycle stages outside their animal host. Furthermore, the spatial distribution and availability of pasture and water are highly dependent on the pattern and availability of rainfall. Shortage of feed and water contribute to reduced productivity and reproductive performance of livestock. This includes slow growth rate of animals, loss of body condition, reduced milk production and poor reproductive performance in mature animals. Draught oxen that are emaciated and in poor body condition cannot provide adequate draught power for plowing, and thus affects crop cultivation. Bush encroachment as well as population pressure lead to diminishing availability of good pasture and hence to a decline in the total number of animals. Different adaptation options are followed by Livestock owners, such as Conservation of feed, out-migration of some household members to earn additional income, destocking, settlement and intensification of livestock production, undertaking supplementary income generating activities and awareness creation on the factors affecting climate change.

Effect of hop (Humulus lupulus L.) inclusion in the diet for fattening lambs on animal performance, ruminal characteristics and meat quality

Thirty male merino lambs were fed with a pelleted total mixed ration (TMR) alone or supplemented with hop (Humulus lupulus L.) cones at two different doses (1.5 and 3.0 g hop cones/kg pelleted TMR, respectively), to study the effects of this dietary source of antioxidants on animal performance, ruminal parameters and meat quality attributes. The results showed that dietary supplementation with hop cones decreased lambs' growth rate (P < 0.05) due to a shift in ruminal fermentation, towards a more acetic and less propionic acid production (P < 0.05). These changes in animal growth rate might have promoted microstructural modifications in the quantity and size of muscle fibres, thereby inducing the differences observed in meat chemical composition, colour and texture (P < 0.05), regardless of the lack of differences in meat antioxidant status (P > 0.10).

A widespread morphological antipredator mechanism reduces the sensitivity to pesticides and increases the susceptibility to warming

Pollution and predation are two omnipresent stressors in aquatic systems that can interact in multiple ways, thereby challenging accurate assessment of the effects of pollutants in natural systems. Despite the widespread occurrence of morphological antipredator mechanisms, no studies have tested how these can affect the sensitivity of prey to pesticides. Sensitivity to pesticides is typically measured via reductions in growth rates and survival, but also reductions in heat tolerance are to be expected and are becoming increasingly important in a warming world. We investigated how autotomy, a widespread morphological antipredator mechanism where animals sacrifice a body part (here the caudal lamellae) to escape when attacked by a predator, modified the sensitivity to the insecticide chlorpyrifos in larvae of the damselfly Coenagrion puella. Exposure to chlorpyrifos reduced the growth rate and heat tolerance (measured as CTmax). A key finding was that the pesticide had a greater impact on growth rates of intact animals, i.e. those that retained their lamellae. This reduced sensitivity to chlorpyrifos in animals without lamellae can be explained by the reduced outer surface area which is expected to result in a lower uptake of the pesticide. Larvae that underwent autotomy exhibited a lower heat tolerance, which may also be explained by the reduced surface area and the associated reduction in oxygen uptake. There is a wide diversity of morphological antipredator mechanisms, suggesting that there will be more examples where these mechanisms affect the vulnerability to pollutants. Given the importance of pollution and predation as structuring forces in aquatic food webs, exploring the potential interactions between morphological antipredator mechanisms and sensitivity to pollutants will be crucial for risk assessment of pollutants in aquatic systems.

Spatial and Temporal Variability in Growth of Giant Gartersnakes: Plasticity, Precipitation, and Prey

Abstract The growth rate of reptiles is plastic and often varies among individuals, populations, and years in response to environmental conditions. For an imperiled species, the growth rate of individual animals is an important component of demographic models, and changes in individual growth rates might precede changes in abundance. We analyzed a long-term dataset on the growth of Giant Gartersnakes (Thamnophis gigas) to characterize spatial and temporal variability and evaluate potential environmental predictors of growth. We collected data on the growth in snout–vent length (SVL) of Giant Gartersnakes over 22 yr (1995–2016) from eight sites distributed throughout the Sacramento Valley of California, USA. The von Bertalanffy growth curves indicated male Giant Gartersnakes grew faster toward shorter, asymptotic SVL than did females. Nearly equal variability in growth was attributable to differences among years and among sites. From 2003–2016 we collected data on precipitation, temperature, and the abunda...

Effect of increase in temperature on the survival and growth ofMacrobrachium amazonicum(Palaemonidae) in the Amazon

Macrobrachium amazonicumis a shrimp species distributed in freshwater habitats of Neotropical regions and is of great importance for the Amazonian economy. This study evaluated the effects of temperature increase on the survival and growth ofM. amazonicum. For this, we distributed 360M. amazonicumjuveniles in 70 L tanks, and carried out a 90-day experiment with three treatments (T0: 28 ± 0.5 °C, or room temperature; T1: 30 ± 0.2 °C; T2: 32 ± 0.2 °C), using 4 replicate tanks each with 30 individual shrimp. Culture-tanks were connected to a recirculation system with biofiltration and constant aeration. Animals were fed twice a day using shrimp pelleted commercial food. After 90 days of trial, the total length and body mass gain of the animals cultured at room temperature was 78% and 433%, respectively. The specific growth rate, condition factor, weight gain, and length and survival of animals cultured at 30 and 32 °C were lower than those cultivated at 28 °C, and feed conversion was higher. Therefore, water temperature of 30 and 32 °C may compromise growth and survival ofM. amazonicumduring cultivation, none of the extreme temperatures may be recommended in practice.

Therapeutic Effect of Glycyrrhizin Arginine Salt on Rat Cholestatic Cirrhosis and its Mechanism.

To investigate the therapeutic effect of glycyrrhizin arginine salt on rat cholestatic cirrhosis, we subjected male Sprague Dawley rats to common bile duct ligation for 14 days and treated them with distilled water (model group), arginine, or a low or high dose of glycyrrhizin arginine salt by gavage. A sham-operated group was used as a control group. Treatment with glycyrrhizin arginine salt substantially improved animal growth rates, reduced the ratio of liver weight to body weight and decreased total bilirubin, aspartate aminotransferase, 8-isoprostane and malondialdehyde compared with the values measured in the model group. The progress of liver fibrosis, as detected by hematoxylin and eosin and Masson's trichrome staining, was slower in the glycyrrhizin arginine salt groups than in the model group or the arginine group. Reductions of bile salt pool size, hepatic hydroxyproline content and fibrosis score were also seen in the glycyrrhizin arginine salt groups compared with the model group. Furthermore, glycyrrhizin arginine salt significantly reduced the expression of transforming growth factor [Formula: see text]1 (TGF-[Formula: see text]1), [Formula: see text]-smooth muscle actin, tumor necrosis factor-[Formula: see text] and matrix metalloproteinases 2 and 9. Glycyrrhizin arginine salt also inhibited the expression of [Formula: see text]-SMA and matrix metalloproteinases 2 and 9 in response to TGF-[Formula: see text]1 in LX-2 cells and primary rat hepatic stellate cells and mitigated the cytotoxicity induced by rat bile in HepG2 cells and primary rat hepatocytes.

Use of Different Types and Amounts of Dietary Fats to Redesign Pork

Title: Use of different types and amounts of dietary fats to redesign pork. Background: Using high energy fat-supplemented diets in pork production can offer several economic advantages to producers when fat sources are cost effectively priced. Because of a decreased heat increment, dietary fat supplementation allows a greater proportion of dietary calories to be available for tissue synthesis when pigs are maintained at or above the thermo neutral zone. Previous research has indicated that diets that have increasing dietary saturated fatty acids (SFA) cause hypercholesterolemia, atherosclerosis development, and greater coronary heart disease risk in humans. When dietary polyunsaturated fatty acids (PUFA) are substituted for saturated fatty acids (SFA), decreased blood cholesterol concentration occurs. This information has caused the consumer to question the consumption of meat products, such as pork, which are perceived as being rich in SFAs. The objective of this study was to alter the polyunsaturated (PUFA) to saturated fatty acid (SFA) ratio in pork for better human nutrition. Methods and findings: Pigs were fed either choice white grease or soybean oil at 10, 20, 30, or 40% of total dietary calories. All diets were based on corn and soybean meal. The study used 54 pigs with six pigs per treatment. Initial and slaughter weights were 54 and 110 kg, respectively. Skeletal muscle samples were taken from the longissimus dorsi, biceps femoris, and triceps brachii muscles. Adipose tissue samples were taken from the outer, middle, and inner 10th rib backfat layers, perirenal adipose tissue, and an inter muscular adipose deposit within the ham. Total lipids were extracted; fatty acid methyl esters were formed by trans esterification and quantified by gas chromatography. Adding choice white grease or soybean oil to diets fed growing swine did not alter animal growth rates. The PUFA from the outer 10th rib backfat layer showed linear increases (P < 0.05) when pigs were fed diets with increasingly greater soybean oil content, whereas the backfat from pigs fed diets containing greater choice white grease contents resulted in a linear increase (P < 0.05) of monounsaturated fatty acids (MUFA). Including soybean oil in the low-fat control diet at 30 and 40% increased the PUFA to SFA ratios (P:S) to 0.9 and 1.26 (P < 0.05), respectively, in longissimus muscle. The MUFA content in the longissimus muscle was decreased by 30% (P < 0.05) with the 40% soybean oil diet. Myristate, palmitate, and total SFA in longiIIssimus muscle decreased 27 (P < 0.05), 30 (P < 0.05), and 29% (P < 0.05), respectively, with the 40% soybean oil diet. Conclusions: Including choice white grease in the diet had minimal effects on the unsaturated to SFA muscular lipid ratios. In conclusion, high fat diets rich in unsaturated fatty acids can be used effectively to redesign pork for consumers wanting to decrease their consumption of saturated fatty acids.

Genome sequencing of Pediococcus acidilactici (NRCC1), a novel isolate from dromedary camel (Camelus dromedarius) rumen fluid

The lactic acid bacterium Pediococcus acidilactici has recently been reported to help in treating constipation, diarrhea, relieving stress, and enhancing growth rate and immune response in humans, birds, fishes, and small animals. In the present study, we sequenced and analyzed the whole genome of P. acidilactici NRCC1, a novel isolate from rumen fluid of dromedary camel (Camelus dromedarius). The genome of P. acidilactici NRCC1 was assembled into 60 contigs, comprising 1,785,679 bp and 42.5% GC content. The 1705 CDS were predicted and annotated using the RAST server. The genome encodes numerous enzymes for utilization of different carbohydrates. It also harbors genes for antibiotic biosynthesis and many others which might confer probiotic properties. The comparative genome analysis with P. acidilactici DSM 20284 revealed some unique features in P. acidilactici NRCC1. Thus, the genome sequencing of P. acidilactici NRCC1 has opened up new horizons for further research in animal probiotics and feed supplements.

Lead Emissions and Population Vulnerability in the Detroit (Michigan, USA) Metropolitan Area, 2006-2013: A Spatial and Temporal Analysis.

Objective: The purpose of this research is to geographically model airborne lead emission concentrations and total lead deposition in the Detroit Metropolitan Area (DMA) from 2006 to 2013. Further, this study characterizes the racial and socioeconomic composition of recipient neighborhoods and estimates the potential for IQ (Intelligence Quotient) loss of children residing there. Methods: Lead emissions were modeled from emitting facilities in the DMA using AERMOD (American Meteorological Society/Environmental Protection Agency Regulatory Model). Multilevel modeling was used to estimate local racial residential segregation, controlling for poverty. Global Moran’s I bivariate spatial autocorrelation statistics were used to assess modeled emissions with increasing segregation. Results: Lead emitting facilities were primarily located in, and moving to, highly black segregated neighborhoods regardless of poverty levels—a phenomenon known as environmental injustice. The findings from this research showed three years of elevated airborne emission concentrations in these neighborhoods to equate to a predicted 1.0 to 3.0 reduction in IQ points for children living there. Across the DMA there are many areas where annual lead deposition was substantially higher than recommended for aquatic (rivers, lakes, etc.) and terrestrial (forests, dunes, etc.) ecosystems. These lead levels result in decreased reproductive and growth rates in plants and animals, and neurological deficits in vertebrates. Conclusions: This lead-hazard and neighborhood context assessment will inform future childhood lead exposure studies and potential health consequences in the DMA.

Risk of prophylactic antibiotics in livestock and poultry farms; a growing problem for human and animal health

Purpose: Veterinary antibiotics are physiologically highly active substances which are being used on a large scale as therapeutic drugs and as feed additives in modern agricultural practice. Major purposes of use of antibiotics are prevention and treatments of bacterial infections and for the improvements of growth rates of farm animals. Therefore, the present study was focused on quantification of some selected groups of antibiotics; tetracycline [Tetracycline (TET), Oxytetracycline (OTC)] and penicillin [Amoxicillin (AMX), Ampicillin (AMP)] in wastewater discharge drains in large-scale livestock and poultry farms and to isolate antibiotic resistant bacteria. Methods: Twenty wastewater discharge drains in livestock and poultry farms were selected to collect samples for the study. Solid-Phase Extraction (SPE) was employed and antibiotic quantification was done by High Performance Liquid Chromatography (HPLC). Isolation of resistance (r) bacteria was done by standard pour plate method where Minimum Inhibitory Concentration (MIC) of bacteria was determined using the range of 60 to 720ppm concentrations of the antibiotics by agar dilution method. Results: Oxytetracycline (55%), and tetracycline (38%) were recorded as most frequent antibiotics in samples and having concentrations of 0.005 ppm and 0.004 ppm respectively. The highest concentration of AMX was recorded as 0.003±0.004 ppm. However, AMP was not detected during the study period. Oxytetracycline and tetracycline resistance bacteria were identified as Enterococcus sp., E. faecium, E.coli and Clostridium sp. while, A. baumanii, E. clocae, A. lwoffii and H.pylori were identified as AMPr and AMXr bacteria by 16S rRNA sequencing. The MIC values of tetracycline (TET, OTC) resistant bacteria ranged from 360 ppm to 720 ppm whereas for penicillin (AMX, AMP) from 360 to 760 ppm. Conclusion: The contamination of antibiotics leads to develop antibiotic resistance in environmental bacteria. Thus, the results of the study indicate that presence of antibiotic resistant bacteria may limit the effectiveness of antibiotics in treating animal illness, thereby causing a potential risk to the productivity of livestock and poultry farms.

The relationship between Norwegian Red heifer growth and their first-lactation test-day milk yield: A field study

Today's Norwegian Red (NR) is markedly different from the one that existed 25 yr ago due to the continuous genetic improvement of economically important traits. Still, current national recommendations on replacement heifer rearing largely are based on results from Danish studies from the late 1980s to the mid 1990s. The objectives of the present study were to gain information on (1) growth and growth profiles of modern NR replacement heifers in commercial dairy herds and (2) how growth during the rearing period affects the heifers' milk yield during their first lactation. To this end, we conducted a field study on 5 high-producing and 5 low-producing commercial dairy farms from each of 3 geographical regions in Norway. On these 30 farms, we combined repeated onsite registrations of growth on all available females from newborn to calving with registrations deriving from the Norwegian Dairy Herd Recording System. Each herd was visited 6 to 8 times over a period of 2 yr. At each visit, heart girth circumference on all available young females was measured. Registrations were made on a total of 3,110 heifers. After imposing restrictions on the data, growth parameters were estimated based on information from 536 animals, whereas 350 of these animals had the required information needed to estimate the relationship between growth and test-day milk yield. Our findings pointed toward an optimal ADG of 830 g/d from 10 to 15 mo of age that would optimize first-lactation yield of heifers in an average Norwegian dairy herd. The optimum will likely increase from selection over time. Utilizing simple proportionality, the ADG between 5 and 10 mo of age ideally should be 879 g/d, taking into account the fact that animal growth rate is higher at low ages and that a high prepubertal growth rate had no negative effect on first-lactation yield. When such a rearing practice is used to meet the requirements of today's genetically improved NR heifer, heifers can both optimize production in their first lactation and enter the milking herd earlier than the current average age of 24.8 mo.

Global gene expression in muscle from fasted/refed trout reveals up-regulation of genes promoting myofibre hypertrophy but not myofibre production

BackgroundCompensatory growth is a phase of rapid growth, greater than the growth rate of control animals, that occurs after a period of growth-stunting conditions. Fish show a capacity for compensatory growth after alleviation of dietary restriction, but the underlying cellular mechanisms are unknown. To learn more about the contribution of genes regulating hypertrophy (an increase in muscle fibre size) and hyperplasia (the generation of new muscle fibres) in the compensatory muscle growth response in fish, we used high-density microarray analysis to investigate the global gene expression in muscle of trout during a fasting-refeeding schedule and in muscle of control-fed trout displaying normal growth.ResultsThe compensatory muscle growth signature, as defined by genes up-regulated in muscles of refed trout compared with control-fed trout, showed enrichment in functional categories related to protein biosynthesis and maturation, such as RNA processing, ribonucleoprotein complex biogenesis, ribosome biogenesis, translation and protein folding. This signature was also enriched in chromatin-remodelling factors of the protein arginine N-methyl transferase family. Unexpectedly, functional categories related to cell division and DNA replication were not inferred from the molecular signature of compensatory muscle growth, and this signature contained virtually none of the genes previously reported to be up-regulated in hyperplastic growth zones of the late trout embryo myotome and to potentially be involved in production of new myofibres, notably genes encoding myogenic regulatory factors, transmembrane receptors essential for myoblast fusion or myofibrillar proteins predominant in nascent myofibres.ConclusionGenes promoting myofibre growth, but not myofibre formation, were up-regulated in muscles of refed trout compared with continually fed trout. This suggests that a compensatory muscle growth response, resulting from the stimulation of hypertrophy but not the stimulation of hyperplasia, occurs in trout after refeeding. The generation of a large set of genes up-regulated in muscle of refed trout may yield insights into the molecular and cellular mechanisms controlling skeletal muscle mass in teleost and serve as a useful list of potential molecular markers of muscle growth in fish.

Immunosurveillance and immunoediting in MMTV-PyMT-induced mammary oncogenesis

ABSTRACTEvidence of cancer immunosurveillance and immunoediting processes has been primarily demonstrated in mouse models of chemically induced oncogenesis. Although these models are very tractable, they are characterized by high mutational loads that represent a minority of human cancers. In this study, we sought to determine whether cancer immunosurveillance and immunoediting could be demonstrated in a more clinically relevant oncogene-induced model of carcinogenesis, the MMTV-PyMT (PyMT) mammary carcinoma model. This model system in the FVB/NJ strain background was previously used to demonstrate that adaptive immunity had no role in limiting primary cancer formation and in fact promoted metastasis, thus calling into question whether cancer immunosurveillance operated in preventing the development of breast cancer. Our current study in the C57BL/6 strain backgrounds provides a different conclusion, as we report here the existence of an adaptive immunosurveillance of PyMT mammary carcinomas using two independent models of immune deficiency. PyMT mice bred onto a Rag1−/− background or immune suppressed by chronic tacrolimus therapy both demonstrated accelerated development of mammary carcinomas. By generating a bank of cell lines from these animals, we further show that a subset of PyMT cell lines had delayed growth after transplantation into wild-type (WT) syngeneic, but not immune-deficient hosts. This reduced growth rate in immunocompetent animals was characterized by an increase in immune cell infiltration and tissue differentiation. Furthermore, loss of the immune cell infiltration that characterized immunoediting of slow growing cell lines, changed them into fast growing variants capable of progressing in the immunocompetent model. In conclusion, our study provides evidence that immunosurveillance and immunoediting of PyMT-derived cell lines modulate tumor progression in this oncogene-induced model of cancer.

Low Molecular Weight Components from Various Sources Eliminate Oxidative Stress and Restore Physiological Characteristic of Animals at Early Stages of Cu- Induced Liver Fibrosis Development

Background: Low molecular weight components (proteins and peptides with a molecular weight less than 45 kDa), were isolated from bovine colostrum and Sacharomyces cerevisue and Pleurotus osteatus cell components. It has been determined their effects on physiological characteristics (weight change, body temperature, work capacity) and biochemical parameters (cholesterol, triacylglycerols, creatinine and albumin) and lipid hydroperoxides (figure prooxidant activity) activity of glutathione peroxidase (a measure of antioxidant system) on the model of Cu-induced liver fibrosis. It is shown that irrespective of the method and the source of the LMWCC and the its components eliminated the loss of body weight, the body temperature normalized, and partially restored working capacity of animals with Cu-induced fibrosis. Methods: A three-fold serial intraperitoneal administration of copper sulfate to animals at the dose of 33% of the lethal dose with an interval of 48 hours between injections was accompanied with development of liver fibrosis. Doses of Mix-factor and LMWCC were chosen for the removed of influence of experimental animal’s fibrosis. In the investigation were used the methods of definition of content of cholesterol, triacylglycerols, creatinine and albumin. Besides, it has been activity of glutathione peroxidase and content of lipid hydroperoxides. Results: Content of cholesterol, triacylglycerols, creatinine and albumin remained unchanged in animals with Cuinduced liver fibrosis, a lipid hydroperoxides have increased by 90% in blood serum and 83% in liver mitochondria and activity of glutathione peroxidase was reduced. Introduction of LMWCC and mix-factor increases the activity of glutathione peroxidase and normalize lipid hydroperoxides content. It has been identified S-shaped dose dependence of LMWCC on indicators of proantioxidant system. Conclusion: The results showed that LMWCC obtained from various sources (from cow colostrum or from Pleurotus ostreatus fungi, or from yeast) activated antioxidant defense enzymes (glutathione peroxidase), eliminated oxidative stress in animals with Cu-induced liver fibrosis. These biochemical changes in the body of animals with fibrosis were accompanied by normalization of physiological characteristics (body temperature, growth rate of animals).

PECULIARITIES OF MUSCULAR, ADIPOSE AND OSSEOUS TISSUE GROWTH IN BOTH PUREBRED AND MIXED BRED BULL-CALVES

Data on morphological carcass composition study in both purebred and mixed bred bull-cal-ves, obtained from crossing black-and-white cows with Aberdeen-Angus and Charolais bulls, are provided in the article. It has been discovered that the carcasses mass of bull-calves increased with age due to more intensive. Lean part growth and skeleton to a lesser degree, Bull-calves, genotype has an important influence on muscu-lar system growth. Inherited potential in musculature growth is better realized in Charolais mongrel bull-calves, the degree of muscular component being 253.6 kg at the age of 18 months, which is by 31.5% bigger than in they black-and-white herdmates. There are no big differences in carcass muscular tissue weight between Aberdeen-Angus crossbreeds and black-and-white Bull-calves. The greatest adipopexis growth by the end of the experiment is a characteristic feature of Aberdeen-Angus crossbreeds. The skeleton growth rate of young animals by comparison during the experimental period is practically the same, but with age the skeleton growth rate decreases significantly in bull-calves.

Effect of diet on growth in captive Podocnemis unifilis: assessing optimal diets for turtles in head-starting programs

Because turtles have come under increasing pressures from habitat loss and over-exploitation as food sources and traditional medicine, efforts have focused on options for conservation, including head-starting programs. Success of head-starting programs depends on establishing economical means of rearing hatchlings over relatively short time frames to sizes resistant to predation. We examined effects of three different diets on growth of a clutch of captive Yellow-spotted Amazon River Turtles (Podocnemis unifilis) over a two-year period in a Florida zoo. Rates of growth differed among the three treatment groups; relationships between morphological variables were not affected by diet. Results indicate that turtles fed on a commercial gel diet may exceed growth rates of animals fed on a more natural, vegetarian diet by more than 15% as measured by straight-line carapace length, or by more than 50% in body mass. Use of a vegetarian diet reduced costs to less than 10% of the cost of a commercial gel diet. Choice of diets for turtles in head-starting programs is a variable that should be weighed against other conservation objectives such as captive duration and intended sizes attained.

Dietary protein and carbohydrate requirement of juvenile Hawaiian limpet (Cellana sandwicensis Pease, 1861) fed practical diet

This study was conducted to evaluate dietary protein and carbohydrate requirement of juvenile Hawaiian limpets Cellana sandwincensis. A total of 64 juvenile limpets (3.12 ± 0.86 g) were fed five different dietary protein levels ranging from 270 to 470 g kg−1 for 90 days. Carbohydrate and lipid levels were held constant at 180 and 49.7 g kg−1, respectively. Weight gain and growth rates of the animals did not differ significantly (P > 0.05) among the protein levels ranging from 270 g kg−1 (0.30 % day−1) to 470 g kg−1 (0.23 % day−1). Next, opihi were fed four diets with protein levels from 210 to 500 g kg−1 with a constant carbohydrate level at 120 g kg−1. Weight gain and specific growth rates of opihi increased with increasing dietary protein from 210 to 350 g kg−1, and significantly (P < 0.05) decreased at the 500 g kg−1 diet. Highest weight gain, growth rates, and protein efficiency ratio were achieved at 350 g kg−1. Elevated carbohydrate levels (180–370 g kg−1) produced a significant difference (P < 0.05) in growth. The fastest growth rates of animals were obtained with 270 g kg−1 (0.27 % day−1) and 320 g kg−1 (0.26 % day−1). The weight gain of animals fed 180 and 370 g kg−1 carbohydrate diets were significantly (P < 0.05) lower than those of animals fed 270 and 320 g kg−1. We conclude that about 350 g kg−1 protein and 320 g kg−1 carbohydrate levels could be used for opihi.

Dietary supplementation with xylanase-expressing B. amyloliquefaciens R8 improves growth performance and enhances immunity against Aeromonas hydrophila in Nile tilapia (Oreochromis niloticus)

Bacillus amyloliquefaciens has attracted attention as a probiotic in aquaculture due to its immunostimulatory activity against pathogenic infection. Xylanases are extensively used in animal feed to degrade plant ingredients, enhancing nutrient utilization and increasing the growth rate of various animals. In the present study, the effects of dietary supplementation with B. amyloliquefaciens and xylanase-expressing B. amyloliquefaciens R8 on the growth of Nile tilapia (Oreochromis niloticus) and immunity against Aeromonas hydrophila were evaluated. The results showed that the xylanase activity in the intestine, weight gain (WG), feed efficiency (FE) and condition factor (CF) of Nile tilapia fed B. amyloliquefaciens R8 for 2 months were significantly increased compared with those of the fish fed the control diet and B. amyloliquefaciens. Moreover, the mRNA expression of growth- and metabolism-related genes, such as insulin-like growth factor-1 (igf-1), glucokinase (GK), glucose-6-phosphate 1-dehydrogenase (G6PD), and glucose-6-phosphatase (G6Pase), was significantly induced in Nile tilapia fed administered B. amyloliquefaciens R8, and this group also exhibited a higher survival rate than the control fish following a challenge with A. hydrophila. The phagocytic activity and respiratory burst activity of head kidney leukocytes as well as the serum lysozyme activity of B. amyloliquefaciens R8-fed Nile tilapia were significantly higher than those of fish fed the control diet for 2 months. Superoxide dismutase (SOD) levels in the head kidney leukocytes of Nile tilapia fed B. amyloliquefaciens R8 differed from those of fish fed the control diet, but this was not significant. These results indicate that dietary supplementation with xylanase-expressing B. amyloliquefaciens R8 improves growth performance and enhances immunity and disease resistance against A. hydrophila in Nile tilapia.

Effects of polymorphism in TG5 and LEP genes on meat productivity of Hereford and Limousin bull calves

The effects of polymorphism in the TG5 and LEP genes on meat productivity of Hereford and Limousin bull calves have been studied under the environmental conditions in the pre-Ural steppe zone. A significant dominance of the TG5C and LepA alleles is determined in the animals of both breeds; the distributions of frequencies of the genotypes for the TG5 gene are similar in character. The most common genotypes are TG5CC and TG5CT. The genotype frequency analysis indicates the considerable genetic potential of the animals for palatability and the nutritional values of meat, which is specified by the relatively high proportions of the TG5T allele and the desirableTG5TT genotype. The breed differences in the frequencies of genotypes for the LEP gene were ascertained as follows: the LEPAA genotype is predominant in the Hereford bull calves, while the relatively useful LEPAB genotype prevails in the Limousin bull calves. No significant relationship between the target TG5 and LEP SNP-genes and the animal growth rates was revealed.