Publications by authors named "Nattrass G"

Introduction: Sex differences in prenatal growth may contribute to sex-dependent programming effects on postnatal phenotype.

Methods: We integrated for the first time phenotypic, histomorphological, clinico-chemical, endocrine and gene expression analyses in a single species, the bovine conceptus at mid-gestation.

Results: We demonstrate that by mid-gestation, before the onset of accelerated growth, the female conceptus displays asymmetric lower growth compared to males.

View Article and Find Full Text PDF

Changing dietary protein and amino acids may impact intestinal barrier function. Experiments were conducted in broiler chickens to evaluate supplementation of L-glutamine, glycine, and L-arginine in a reduced protein (RP) diet. Experiment 1 examined the growth performance of broilers fed 5 dietary treatments: 1) a standard diet; 2) an RP diet (193.

View Article and Find Full Text PDF

Little is known about the effect of low-protein (LP) diets on intestinal barrier function and permeability. In the first part of this study, starting on day 9 of age, the growth performance of the birds fed 3 experimental diets in each phase of feeding (G/F: grower/finisher) was investigated. Three experimental diets were as follows: LP (170/150 g/kg CP) fortified with essential amino acids (EAA), standard protein (SP), (202/190 g/kg), and high protein (HP) (220/210 g/kg).

View Article and Find Full Text PDF

Immune function is influenced by the diversity and stability of the intestinal microbiota. A likely trade-off of immune function for growth has been demonstrated in heavier breeds of poultry that have been genetically selected for growth and feed efficiency traits. We investigated the expression of selected innate immune genes and genes encoding products involved in intestinal barrier function to determine whether function changes could be consistently linked to the phenotypic expression of feed conversion ratio (FCR), a common measure of performance within poultry broiler flocks.

View Article and Find Full Text PDF

The insulin-like growth factor (IGF) axis is fundamental for mammalian growth and development. However, no comprehensive reference data on gene expression across tissues and pre- and postnatal developmental stages are available for any given species. Here we provide systematic promoter- and splice variant specific information on expression of IGF system components in embryonic (Day 48), fetal (Day 153), term (Day 277, placenta) and juvenile (Day 365-396) tissues of domestic cow, a major agricultural species and biomedical model.

View Article and Find Full Text PDF

Background: Divergent selection for meat and egg production in poultry has resulted in strains of birds differing widely in traits related to these products. Modern strains of meat birds can reach live weights of 2 kg in 35 d, while layer strains are now capable of producing more than 300 eggs per annum but grow slowly. In this study, RNA-Seq was used to investigate hepatic gene expression between three groups of birds with large differences in growth potential; meat bird, layer strain as well as an F1 layer x meat bird.

View Article and Find Full Text PDF

Short-term fasting for 4.5 and 9 hr has been demonstrated to increase intestinal permeability (IP) in chickens. This study aimed to investigate the effects of 0, 4.

View Article and Find Full Text PDF

Background: The broiler industry has undergone intense genetic selection over the past 50 yr. resulting in improvements for growth and feed efficiency, however, significant variation remains for performance and growth traits. Production improvements have been coupled with unfavourable metabolic consequences, including immunological trade-offs for growth, and excess fat deposition.

View Article and Find Full Text PDF

The effects of Eimeria (EM) and Clostridium perfringens (CP) challenges on the mRNA levels of genes involved in mucin (Muc) synthesis (Muc2, Muc5ac, Muc13, and trefoil family factor-2 [TFF2]), inflammation (tumor necrosis factor alpha [TNF-alpha] and interleukin-18 [IL-18]), and metabolic processes (cluster of differentiation [CD]36) in the jejunum of broilers were investigated. Two parallel experiments involving 1) EM challenge and 2) EM and CP challenges were conducted. The first experiment was a 2 X 2 study with 12 birds per treatment (N = 48) involving fishmeal substitution (25%) in the diet (FM) and EM challenge.

View Article and Find Full Text PDF

The objective of this study was to investigate whether single nucleotide polymorphisms (SNP) in the calpain 1 (CAPN1), calpain 3 (CAPN3) and calpastatin (CAST) genes, which have been shown to be associated with shear force and tenderness differences in the skeletal muscle of cattle, contribute to phenotypic variation in muscle tenderness by modulating the transcriptional activity of their respective gene. The mRNA expression of the calpain and CAST genes was assessed in the longissimus lumborum muscle (LLM) of cattle from two herds located in distinct production zones on the east (New South Wales, NSW) and west (Western Australia, WA) of Australia. The cattle in the herds were mainly Brahman cattle (Bos indicus) with smaller populations of Angus cattle (Bos taurus).

View Article and Find Full Text PDF

Clostridial infection of the intestine can result in necrotic enteritis (NE), compromising production and health of poultry. Mucins play a major role in protecting the intestinal epithelium from infection. The relative roles of different mucins in gut pathology following bacterial challenge are unclear.

View Article and Find Full Text PDF

Vegetable oils containing stearidonic acid (SDA, 18 : 4n-3) are considered better precursors of long-chain n-3 PUFA (LC n-3 PUFA) than those with only α-linolenic acid (ALA, 18 : 3n-3). The present study re-examined this premise using treatments where added ALA from linseed oil was matched with ALA plus SDA from echium oil. Lambs (n 6) were abomasally infused with saline (control (C), 25 ml), echium oil low (EL, 25 ml), echium oil high (EH, 50 ml), linseed oil low (LL, 25 ml) or linseed oil high (LH, 50 ml) for 4 weeks.

View Article and Find Full Text PDF

Background: When closed reduction of a developmental dislocation of the hip fails, some form of open reduction is required. In recent years, the many advantages of the medial approach open reduction have been emphasized. However, there have been suggestions that the rate of growth disturbance in the proximal femur and the requirement for secondary surgical procedures may be higher with this route than with others.

View Article and Find Full Text PDF

Maternal feed allowance during pregnancy can affect the development of the ovine placenta and fetus. The impact of variations in feed allowance prior to as well as throughout pregnancy has received less attention. Ewes were offered 0.

View Article and Find Full Text PDF

Background: Cerebral palsy is the most common cause of childhood physical disability in developed countries, affecting two children per 1000 live births. Hip displacement affects about one-third of children with cerebral palsy and may result in pain, deformity, and impaired function. The prevention of hip displacement has not been studied in a randomized trial as far as we know.

View Article and Find Full Text PDF

Background: The muscle fiber number and fiber composition of muscle is largely determined during prenatal development. In order to discover genes that are involved in determining adult muscle phenotypes, we studied the gene expression profile of developing fetal bovine longissimus muscle from animals with two different genetic backgrounds using a bovine cDNA microarray. Fetal longissimus muscle was sampled at 4 stages of myogenesis and muscle maturation: primary myogenesis (d 60), secondary myogenesis (d 135), as well as beginning (d 195) and final stages (birth) of functional differentiation of muscle fibers.

View Article and Find Full Text PDF

Aspects of the uptake of the AA Cys, Leu, Ala, and Lys into wool follicles were investigated using short-term culture of thin strips of sheep skin. Following verification of the reliability of the model system, the sites of uptake of the radiolabeled AA were shown to differ and to be consistent with their different roles in fiber production. Cysteine appeared in the zone of keratinization immediately distal to the follicle bulb.

View Article and Find Full Text PDF

Background: Severe crouch gait in patients with spastic diplegia causes excessive loading of the patellofemoral joint and may result in anterior knee pain, gait deterioration, and progressive loss of function. Multilevel orthopaedic surgery has been used to correct severe crouch gait, but no cohort studies or long-term results have been reported, to our knowledge.

Methods: In order to be eligible for the present retrospective cohort study, a patient had to have a severe crouch gait, as defined by sagittal plane kinematic data, that had been treated with multilevel orthopaedic surgery as well as a complete clinical, radiographic, and instrumented gait analysis assessment.

View Article and Find Full Text PDF

Gene expression profiles of LM from beef cattle that underwent significant postweaning undernutrition were studied using complementary DNA (cDNA) microarrays. After 114 d of undernutrition, the RNA from LM showed 2- to 6-fold less expression of many genes from the classes of muscle structural proteins, muscle metabolic enzymes, and extracellular matrix compared with animals on a rapid growth diet. The expression levels of these genes had mostly returned to pretreatment levels after 84 d of realimentation.

View Article and Find Full Text PDF

Between July 2000 and April 2004, 19 patients with bilateral spastic cerebral palsy who required an assistive device to walk had combined lengthening-transfer of the medial hamstrings as part of multilevel surgery. A standardised physical examination, measurement of the Functional Mobility Scale score and video or instrumented gait analysis were performed pre- and post-operatively. Static parameters (popliteal angle, flexion deformity of the knee) and sagittal knee kinematic parameters (knee flexion at initial contact, minimum knee flexion during stance, mean knee flexion during stance) were recorded.

View Article and Find Full Text PDF

The authors studied the outcome of a consecutive series of nine tibiotalocalcaneal fusions for severe calcaneovalgus deformity in five adolescents with severe cerebral palsy. The indications for surgery were severe deformity, pain, brace intolerance, difficulties with shoe wear, and progressive loss of transfer, standing, or walking ability. The goals of surgery were deformity correction, reduced bracing, and ability to wear regular shoes and to maintain function.

View Article and Find Full Text PDF

The effect of varying short-term maternal feed intake during the peri-conception period on the development of ovine fetal muscle at mid-gestation was investigated. Superovulated donor Merino ewes (n = 24) were fed a roughage/grain pelleted diet (10.1 MJME/kg dry matter) at either 1.

View Article and Find Full Text PDF

Most clinicians who perform botulinum toxin A injections for children with cerebral palsy do so using the "free-hand" or manual technique without using radiologic or electrophysiologic guidance to aid needle placement. The objective of this study was to investigate the accuracy of manual needle placement compared with needle placement guided by electrical stimulation. A total of 1,372 separate injections for upper and lower limb spasticity were evaluated in 226 children with cerebral palsy.

View Article and Find Full Text PDF