Effect of biofloc technology on growth of speckled shrimp,Metapenaeus monoceros (Fabricus) in different feeding regimes

The effects of biofloc technology (BFT) were tested on growth performance, water quality, haemolymph parameters and hepatopancreas histology with and without BFT for the speckled shrimp. In this study, eight different experimental groups were formed (four BFT and four control groups) to measure the effects of different feeding rates on compensatory growth of speckled shrimp. BFT treatments were performed with zero water exchange and planned as BFT1: gradually feed decreasing group 4, 2 and 1% bw, BFT2: 4% bw, BFT3: 2‐days feed with 4% bw, 1‐day fasted, and BFT4: 1‐day feed with 4% bw, 1‐day fasted. In control treatment, the same trial groups were constituted for comparing with BFT at a 50% daily water exchange: C1 (gradually feed decreasing group: 4%, 2% and 1% bw), C2 (4% bw), C3 (2‐days feed with 4% bw, 1‐day fasted), C4 (1‐day feed with 4% bw, 1‐day fasted). There were significant differences between BFT and C groups in terms of some water quality (p < 0.05). In general, BFT had an effect on haemocyte profile. At the histological examination, there were no pathological findings in both BFT and control groups. The growth parameters of speckled shrimps in BFT groups, as well as the whole body crude protein ratios and crude ash contents, were higher than the control group (p < 0.05). The results confirmed that biofloc utilization increased with decreasing feeding.     

The use of microsatellite polymorphisms to characterise and compare genetic variability in Avena strigosa and A. barbata

Microsatellite (SSR) polymorphism was assessed across 90 diploid Avena strigosa Schreb. and tetraploid Avena barbata Pott ex Link accessions obtained from the USDA-ARS National Small Grains Collection using 105 genomic SSRs. Eleven polymorphic SSRs that detected 69 different alleles were identified and used to genotype the 90 accessions, which were chosen from a larger set of 385 accessions based on geographical source-diversity and variable reaction responses to five Australian pathotypes of the crown rust pathogen Puccinia coronata Corda f. sp. avenae Eriks. Eight diploid and eight tetraploid clades were identified among the 90 accessions. Diploid accessions displayed the lowest genetic diversity, with all accessions being at least 86 % similar, and included accessions from countries in the Americas such as Canada, USA, Argentina, Uruguay and Brazil, and European accessions from France, Romania and Poland. Although both species formed distinct clusters in the dendrogram, a few instances of diploids showing high similarity with tetraploids and vice versa were observed. An AMOVA analysis revealed 86 % of the total genetic variation to be distributed within the two oat species, while between-species differences accounted for only 14 %. Heterozygosity (H) index values of 0.32 and 0.40 were obtained for diploids and tetraploids respectively. Our study effectively differentiated A. strigosa and A. barbata, and identified 11 SSRs suitable for future characterisation of accessions of the two species.     

Effect of breed on fattening performance, slaughter and meat quality characteristics of Awassi and Morkaraman lambs

The influence of breed on fattening performance, slaughter and meat quality traits was studied in Awassi and Morkaraman male lambs at approximately 8 months of age. All of the groups were fed a diet consisting of concentrate mixture offered ad libitum, and 300 g of grass hay per lamb per day during 60-day fattening period. Initial live weight, final live weight, daily weight gain and feed conversion efficiency (concentrate and hay consumption for 1 kg of live weight gain) were 39.63 kg, 55.08 kg, 0.258 kg and 6.37 for Awassi; 40.54 kg, 55.58 kg, 0.234 kg and 6.77 for Morkaraman, respectively. The effect of breed on fattening performance and slaughter traits except for LD area was not significant. In addition, meat colour parameters (L = lightness, a = redness, b = yellowness, H = hue angle and C = chroma), pH values, drip loss and sensory attributes were not affected by breed in present study. A significant muscle effect was observed for instrumental measurements of some meat quality characteristics as meat colour parameters (L, a and C), collagen, drip loss, pH, moisture and protein content, WBS, and for some sensory attributes (tenderness, juiciness, acceptability and number of chewing). Results of this study indicate that fattening performance, slaughter and meat quality traits were similar between Awassi and Morkaraman male lambs.     

Development,characterization and application of genomic SSR markers for the oat stem rust pathogen Puccinia graminis f. sp. avenae

Oat stem rust, caused by Puccinia graminis f. sp. avenae (Pga), is one of the most severe diseases of oats worldwide. Population studies are scarce for this pathogen, mainly due to the lack of polymorphic molecular markers suitable for genetic analysis. In this study, an Australian Pga isolate was sequenced, the abundance of simple sequence repeats (SSRs) was determined and PCR‐based polymorphic markers suitable for genetic diversity analysis were developed. The amplification of 194 primer pairs was initially assessed using a set of 12 isolates of different cereal rust species and their formae speciales. A high frequency of cross‐species amplification was observed for most markers; however, 36 SSRs were diagnostic for P. graminis only. A subset of 19 genome‐derived SSRs were deemed useful for genetic diversity analysis of Pga and were assessed on 66 Pga isolates from Australia, Brazil and Sweden. Brazilian and Australian isolates were characterized by one and two predominant clonal lineages, respectively. In contrast, the Swedish isolates, previously shown to undergo sexual recombination, were highly diverse (nine distinct genotypes out of 10 isolates) and divided into two subpopulations. The genome‐derived SSR markers developed in this study were well suited to the population studies undertaken, and have diagnostic capabilities that should aid in the identification of unknown rust pathogen species.     

Characterization of two new <Emphasis Type="Italic">Puccinia graminis</Emphasis> f. sp. <Emphasis Type="Italic">tritici</Emphasis> races within the Ug99 lineage in South Africa

Two new races of the wheat (Triticum aestivum L.) stem rust pathogen, representing the fifth and sixth variants described within the Ug99 lineage, were detected in South Africa. Races TTKSP and PTKST (North American notation) were detected in 2007 and 2009, respectively. Except for Sr24 virulence, race TTKSP is phenotypically identical to TTKSF, a commonly detected race of Puccinia graminis f. sp. tritici (Pgt) in South Africa. PTKST is similar to TTKSP except that it produces a lower infection type on the Sr21 differential and has virulence for Sr31. Simple sequence repeat (SSR) analysis confirmed the genetic relationship amongst TTKSF, TTKSP, PTKST and TTKSK (Ug99). TTKSK, PTKST and TTKSF grouped together with 99% similarity, while sharing 88% genetic resemblance with TTKSP. These four races in turn shared only 31% similarity with other South African races. It is proposed that both TTKSP and PTKST represent exotic introductions of Pgt to South Africa.     

A study on possibility of Rosa canina seed use as feed ?ngredient in diets of Morkaraman male lambs

This experiment was carried out to evaluate the ground Rosa canina seed at various levels (0%, 5%, and 15%) in barley-soybean-based concentrates offered to Morkaraman male lambs at approximately 8?months of age, on fattening performance, carcass, and meat quality characteristics. The lambs were divided into three treatment groups including R1 (concentrate without R. canina seed; n?=?12), R2 (concentrate with 5% R. canina seed; n?=?12), and R3 (concentrate with 15% R. canina seed; n?=?12) at the beginning of fattening period. The soybean meal was used as main protein source in treatment groups. All of the groups were fed a diet consisting of concentrate offered ad libitum and 300?g of grass hay per lamb per day during 60-day fattening period. The effect of diet on daily weight gain was found statistically significant. The control group had higher daily weight gain than R3 groups with 15% of ground R. canina seed. The hot carcass and cold carcass weights and dressing percentage values were affected by diets, and R3 group fed concentrate with 15% R. canina seed had higher carcass weights and dressing percentages than R1 and R2 groups. Differences among the groups in terms of leg, rib, and hindshank weights were found highly significant. While R1 and R2 groups were not significantly different, R3 group was significantly higher to R1 and R2 groups in leg, rib, and hindshank weights. In addition, meat color parameters and pH values were not affected by diets in present study.     

Simple sequence repeat markers support the presence of a single genotype of Puccinia psidii in Australia

A non‐native rust of Myrtaceae was first detected in Australia in 2010, and was later identified as Puccinia psidii. The presence of many native species of Myrtaceae and a lack of understanding of genetic variability in P. psidii in Australia led to the current study. Low coverage genome sequencing of P. psidii suggested a genome size of c. 142 Mb. A set of 240 simple sequence repeat (SSR) primers was designed based on the genome sequence information generated. Seventeen isolates of P. psidii comprising 14 from Australia, two from Brazil and one from Hawaii were selected to study genetic variation in the pathogen. Out of 240 initially screened markers, 74% showed amplification among P. psidii isolates and 38% were polymorphic. Primers were fluorescently labelled and genotyping revealed three distinct genotypes among the isolates: one comprising Australian isolates and an isolate from Hawaii, and the second and third comprising two Brazilian isolates. Locus USYD_Pp151 produced a fourth genotype for the Hawaiian isolate of P. psidii. Markers revealed that all Australian isolates were genetically similar to the one from Hawaii. There was no genetic variation among the Australian isolates of P. psidii, supporting the hypothesis that only one genotype of P. psidii was introduced into Australia. The SSR markers developed in this study are highly specific to P. psidii and can be used confidently as a new profiling tool to monitor evolution of P. psidii in Australia and elsewhere.     

Effects of organically-complexed minerals on meat quality in chickens

1. The impact of combined lower concentrations of organically-complexed versus inorganic copper, zinc and manganese on meat quality in chickens was investigated.

2. A total of 200 male broiler chicks (Ross-308), 1-d-old and weighing approximately 40?g, were divided into 4 groups comprising three experimental groups and one control group, with each consisting of 50 chicks. All groups were also divided into 5 subgroups, with each containing 10 broiler chicks.

3. All birds were given a starter diet from d 1 to d 21, and a grower diet from d 22 to d 49. The diets were formulated according to the NRC recommendations.

4. The mineral contents of the control diet were supplied using a standard inorganic mineral premix (containing 8?mg Cu as CuSO₄, 40?mg Zn as ZnSO₄, and 60?mg Mn as MnO, per kg). For the experimental diets, a mineral premix was prepared using organically complexed forms of those minerals at 1/3 (L1), 2/3 (L2) and 3/3 (L3) proportions.

5. After slaughtering and evisceration, the carcases were stored at 3?±?0·5°C for 10–12?h, and then the breast fillets removed from the carcases, and stored in a deep-freezer (?86°C) until analysis (for 30?d). For analyses, the breast muscles were then thawed at 4–6°C for 24?h.

6. The concentration of organically complexed mineral in the diet had no statistically significant effect on pH values of breast fillets. Treatments significantly affected the Thiobarbituric Acid Reactive Substances (TBARS) values.

7. Lightness (L* value) of the fillet from broilers fed the diet containing inorganic minerals was significantly lower than that for broilers fed on the diets containing organically complexed minerals. The redness (a* value) and Chroma (C* value) significantly decreased while Hues (H* value) were higher in the fillet from broilers fed organically complexed minerals compared with those fed inorganic minerals. The yellowness (b* value) was not changed by dietary treatment.