Interaction between the sequence of feeding of hay and concentrate,and boiling of barley on feed intake,the activity of hydrolytic enzymes and fermentation in the hindgut of Arabian mares

The interaction between the sequence of feeding of hay and concentrate and the hydrothermal processing of barley in alleviating concentrate effects on intake, and hindgut fermentation in horses was tested. Six Arabian mares (4–10 years of age, 410 ± 35 kg body weight) were used to evaluate the effects of feeding sequence (FS) and type of barley (TB) on intake, and faecal volatile fatty acids (VFA), activities of α‐amylase (AA: EC 3.2.1.1), carboxymethyl cellulase (CMCase: EC 3.2.1.4), microcrystalline cellulase (MCCase: EC 3.2.1.91) and general filter paper degrading activity (FPD). Mares were offered a ration of air‐dried alfalfa and concentrate (70:30 as‐fed) in four subsequent periods of 14 days including 8 days of adaptation and 6 days of sampling. In each period and each meal, mares received concentrate either 30 min after (HC) or 30 min before (CH) alfalfa hay. Barley was either milled or boiled in water. Rectal samples were grabbed directly from rectum once per period. Mares subjected to CH had higher dry matter intakes than mares under HC regime. The acetate:propionate ratio (A:P ratio) in rectal content was higher with CH than HC. The AA activity was higher under CH than under HC. Mares fed boiled barley had lower rectal concentrations of VFA and propionate and a higher A:P ratio than mares fed milled barley. Furthermore, the rectal content showed a higher MCCase activity but a lower AA activity when mares were fed boiled compared with milled barley. Interactions between FS and TB were observed with respect to CMCase activity, and concentrations of propionate and valerate. In conclusion, the present results suggest that both, feeding concentrate before hay and boiling the barley, might improve the hindgut environment in Arabian mares, and that the two measures were mostly additive and sometimes even synergistic.     

Effects of different carbon sources and dietary protein levels in a biofloc system on growth performance,immune response against white spot syndrome virus infection and cathepsin L gene expression of Litopenaeus vannamei

A 5‐week study was performed to evaluate the effect of spoilage date extract (SDE) as the biofloc carbon source on Litopenaeus vannamei (5.4 ± 0.3 g) performance. The two levels of dietary protein (15% and 25% crude protein) and two carbohydrate sources (molasses‐M and SDE‐P) were tested including: M15, M25, P15 and P25. The minimum (0.2 ± 0.0 mg/L) and the maximum (0.5 ± 0.0 mg/L) of total ammonia nitrogen were observed in the P15 and M25 groups respectively. The highest protein efficiency ratio (6.1 ± 0.3) and protein productive value (112.3 ± 5.8%) were found in the P15 group (p < 0.05). No significant difference was found between biofloc treatments in the expression of cathepsin L gene in hepatopancreas (p > 0.05). The number of total haemocyte count (THC), semigranular cells (SGC) and granular cells (GC) of shrimp in SDE‐based biofloc treatments was relatively higher than those in molasses‐based biofloc treatments. Following the white spot syndrome virus (WSSV) challenge, a significant decrease in THC, SGC, GC and hyaline cell values was observed in all treatments (p = 0.001). Plasma biochemical parameters were significantly influenced by dietary protein levels, biofloc carbon sources as well as WSSV challenge test. In conclusion, SDE successfully could be used as an alternative carbon source for establishing a biofloc system in L. vannamei production.     

Simultaneous selection for seed and forage production in cocksfoot (Dactylis glomerata): application of drought tolerance and susceptibility indices

An experiment was conducted to estimate drought tolerance of some cocksfoot genotypes based on seed and forage yield and related indices (including tolerance index, mean productivity, geometric mean productivity, reduction percentage index, stress tolerance index and stress susceptibility index) and to identify relationships between measured traits. Twenty‐five genotypes were evaluated in the field under control and drought‐stress environments over 2 years. The results revealed a high variation for seed yield and forage yield and the measured indices under both moisture conditions. No correlation was observed between seed yield and forage yield under the control treatment, but this correlation was positively significant under the water‐stress treatment. Drought‐tolerant and susceptible genotypes were identified based on seed and forage yield performance. Genotypes 2, 4 and 7 had high seed yield, while genotypes 7 and 10 had high forage yield under both stressed and non‐stressed conditions and were identified as the most tolerant genotypes in each category. The results also revealed that genotypes 1, 2, 4, 6, 7, 8 and 24 had relatively high seed and forage yield in both control and drought‐stressed conditions. These genotypes can be used for further studies to improve both seed and forage yields concurrently.     

Evaluation of furrow fertigation and model validation on maize field

In new agricultural practices, joint application of water and fertilizer has been become common. Uniform distribution of fertilizer in soil and in plant growth duration is possible by this procedure. The main objective of this study was to investigate furrow fertigation management effects on distribution uniformity and runoff losses of nitrate in a cornfield, and validate a numerical fertigation model. A field experiment was carried out with seed corn at 12 experiments with a complete randomized block design during 2 years. Nitrogen requirement was determined by soil analysis and accomplished in four stages of the growth: before cultivation, in seven leaves, shooting and earring stages which first section (before cultivation) was applied by manual distribution and others by fertigation. Potash and super phosphate fertilizers (based on soil analysis) were sprayed on soil before planting. Water requirement was estimated by using class a evaporation pan multiplied by plant (Kc) and pan coefficients. Nitrogen fertilizer was solved in irrigation water and injected at the last minutes of irrigation. The results showed that fertilizer distribution uniformity of the low quarter (DU_LQ) ranged from 85.7% to 91.5% in first year, and 69.9% to 95.5% in second year. While water DU_LQ ranged from 74.1 to 98.2% in 2 years. Nitrate losses of surface runoff have ranged between 5.7 and 42.0% in first year according to the application time and the outflow flux. In second year, the nitrate losses decreased by adopting appropriate management based on the experiences of first year. The fertigation model was subsequently applied to the experimental data and results showed good agreement with field data.     

Correction to: Factors affecting reproductive performance in dromedary camel herds in Saudi Arabia

Tropical Animal Health and Production - This article was originally published with incorrect affiliation 1. The correction affiliation is presented below.     

Effects of dietary myrcene administration on antioxidant gene responses in common carp (Cyprinus carpio), exposed to copper sulphate

In the present study, common carp (Cyprinus carpio) were fed with diet supplemented with 0% (M0) or 0.5% (M0.5) myrcene for 6 week and exposed to ambient copper (0.2 mg/L) for further 2 weeks. Gene expressions of superoxide dismutase (sod), catalase (cat), glutathione peroxidase (gpx), glutathione reductase (gr) and glutathione S‐transferase (gst) were assayed in the fish brain and kidney, and thiobarbituric reactive substance (TBARS) levels were determined in blood plasma. The results showed that there was no significant difference in TBARS levels between the M0 and M0.5 treatments, before the copper exposure; however, the M0 had significantly higher TBARS levels compared to the M0.5, after the copper exposure. The antioxidant genes showed different patterns in the fish brain and kidney. The genes were up‐regulated in the fish brain by dietary myrcene and copper exposure. However, in the fish kidney, the M0.5 treatment showed no change in sod, cat, gpx before and after the copper exposure. The results suggest that myrcene is capable to induce antioxidant enzymes that prepare the fish for a further oxidative condition (i.e. copper exposure). Dietary myrcene at 0.5% level is suggested for common carp before treatment with copper sulphate.     

Effects of dietary tryptophan levels and fish stocking density on immunological and antioxidant responses and bactericidal activity against Aeromonas hydrophila in rainbow trout (Oncorhynchus mykiss)

Rainbow trout (Oncorhynchus mykiss) was reared under low (LD) and high (HD) stocking densities for 70 days, during which they were fed with diets supplemented with 0, 5 and 10 g tryptophan (Trp) per kg. At the end of the experiment, there were significant interaction effects of the stocking density and Trp levels on plasma Trp, globulin, lysozyme, catalase (CAT), malondialdehyde (MDA), and bactericidal activity and blood leucocyte count. However, there was no difference in plasma complement (ACH50), total immunoglobulin (Ig), total antioxidant capacity (TAC), superoxide dismutase (SOD) and blood differential leucocyte count. Trp at 5 g per kg diet significantly increased lysozyme and bactericidal activity, and decreased MDA under both the LD and HD conditions. Moreover, it significantly increased plasma CAT and blood leucocyte under the LD and HD conditions respectively. Trp at 10 g per kg diet significantly increased blood leucocyte and plasma bactericidal activity under the LD condition, but significantly decreased plasma globulin and bactericidal activity under the HD condition. In conclusion, the present results showed that the effects of Trp on immune and antioxidant systems depend on Trp levels and stressful conditions. As 5 g Trp per kg diet is beneficial for rainbow trout well‐being under both the LD and HD conditions, higher level of Trp (10 g/kg) is not beneficial and even causes some negative effects under the HD condition.     

Dietary ginger administration attenuates oxidative stress and immunosuppression caused by oxytetracycline in rainbow trout (Oncorhynchus mykiss)

In the present study, potential ameliorative effects of dietary ginger (GN) were investigated on antioxidant and immune responses of rainbow trout (Oncorhynchus mykiss) during oxytetracycline (OX) administration. As a 2 × 3 factorial design, the fish were orally treated with OX (a daily dose of 100 mg/kg) and GN (either 10 or 20 g/kg diet) for 10 days. Then, blood samples were taken from each treatment to monitor plasma lysozyme, complement (ACH50), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione‐S‐transferase (GST) activities, and reduced glutathione (GSH), malondialdehyde (MDA), total immunoglobulin (Ig) and globulin levels. OX treatment significantly decreased SOD (30%), GPx, (10%) and lysozyme (23%) activities, and GSH (19%) levels; however, it increased GST (16%) activity and MDA (28%) levels. Ten grams GN per kg levels significantly decreased SOD (35%), CAT (13%), GST (20%) and MDA (30%), but increased GSH (30%), lysozyme (48%) and globulin (16%). Twenty grams GN per kg diet significantly decreased SOD (26%) and MDA (17%), but increased lysozyme (31%) levels. Interaction effects of dietary GN and OX were observed on plasma MDA and GPx levels, as 10 g GN per kg diet prevented the OTC‐induced changes in these parameters. Moreover, 20 g GN per kg diet prevented the OX‐induced change in GPx activity and mitigated the MDA elevation by 20%. It is concluded that GN administration at 10 g/kg diet is beneficial in mitigating oxidative stress and immunosuppression of rainbow trout during OX administration.     

Rainbow trout (<Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>) anesthesia with myrcene: efficacy and physiological responses in comparison with eugenol

The aim of the present study was to investigate anesthetic efficacy of myrcene in rainbow trout (Oncorhynchus mykiss) along with the fish biochemical response to anesthesia in comparison with eugenol. In the first experiment, 240 fish were stocked in 12 tanks and acclimatized to experimental conditions for 2 weeks. Then, the fish of each tank were subjected to one concentration of either eugenol (12, 20, 30, 50, 80, and 130 μL/L) or myrcene (100, 150, 200, 300, 400, and 500 μL/L) concentrations. Induction time of and recovery time from anesthesia were recorded for each fish separately. Using these results, desired concentrations to induce anesthesia within 60, 180, 300, and 600 s were determined, being 81, 30, 19, and 10 μL/L eugenol and 531, 251, 177, and 111 μL/L myrcene. In the second experiment, 96 fish were stocked in 8 tanks. Six fish were netted from each tank and exposed to the calculated eugenol or myrcene concentrations. Blood samples were taken after the fish reached anesthesia. The results showed that there was no significant difference in serum lactate, alanine transaminase, and alkaline phosphatase. Increase in the induction time of anesthesia resulted in increased serum glucose with no significant difference between the anesthetics. Increase in induction time of anesthesia led to increase in serum lactate dehydrogenase activity in the eugenol-anesthetized fish and aspartate transaminase activity in myrcene-anesthetized fish. In conclusion, myrcene is capable to anesthetize rainbow trout, but at higher concentrations compared to eugenol. In addition, biochemical analysis showed that increase in induction time of anesthesia leads to hyperglycemia and increase in AST and LDH activities depending on anesthetic type.     

Calibration of Gypsum Blocks for Measuring Saline Soils Moisture

The proper management of irrigation requires an accurate measuring of soil moisture. One of the commonly applied methods for measuring soil moisture is the use of gypsum blocks – a method that is simple and quick to apply. However, measuring moisture in saline soils using this method is prone to errors due to the effect of soil salinity on the block. In this study, the effect of different salinities (1, 2, 6, 10, and 18 deci Siemens per meter (dS m^?1) on the measurements of a gypsum block type 5910 A was investigated with two repetitions in random blocks in sandy loam, loam, and clay loam soils, and corrective functions were obtained using multivariate regression for all soils with different salinity levels. The results showed different trends for measuring the soil moistures for salinities 1–6 dS m^?1 compared with salinities 10–18 dS m^?1, and the corrective functions in salinities 1–6 dS m^?1, which had higher accuracies than those with salinities 10–18 dS m^?1.