The interest in the search for alternatives to antibiotics in poultry production has been increasing, especially with the focus on essential oils due to their remarkable bioactive properties. This study aimed to investigate the effects of dietary supplementation of essential oils on the performance and gut morphometry of broilers, by using an approach of systematic review and meta-analysis. In the conduction of the systematic review, three electronic databases (PubMed, Science Direct and Scielo) were consulted in January 2023. Out of an initial amount of 162 papers, only 27 met the requisites to be included in the database. Furthermore, after the use of established criteria for the meta-analysis, only 16 papers were qualified for the evaluation of the aimed parameters. In the meta-analysis, it was observed that the supplementation had significant impact (P < 0.05) of 2.88% in weight gain, in comparison to the basal diet. In addition, the supplementation of essential oils significantly improved (P < 0.05) gut morphometry parameters such as villus height in the ileum (15.66% higher), and 8.26% increase in the villus height to crypt depth ratio in jejunum compared to the basal diet. Dietary essential oils improve the growth performance and gut histomorphometry of broilers, even when combined with antibiotics as growth promoters.

The last issue of this Journal (p. 132) contains a paper by Dr R. A. Fisher on the effect of Silica upon the growth of Barley at Rothamsted, which begins by stating that his data “show conclusively that the view previously rejected that the silicate acts by making available to the plant the actual reserves of soil phosphates must be regarded as strongly established.” Twice elsewhere Dr Fisher states that this erroneous conclusion of previous investigators is due to the fact that they had considered only the proportion of phosphoric acid in the ash and had overlooked the increase in the total phosphoric acid in the crop. As Mr Morison and I were the previous investigators in question I turned to our twenty-three-year-old paper with some curiosity to ascertain the grounds for this magisterial dismissal of our conclusions, for my remembrance of the subject did not tally with the opinion Dr Fisher attributes to us. Still less do I agree now that I have re-examined our original paper.

Tropical soils tend to harden during drying due to the generally low content of free-iron and organic carbon, combined with high fine sand and silt proportions. It was hypothesized that the change in soil physical condition induced by the addition of a leguminous mulch in cohesive tropical soil enriched with calcium may mitigate soil hardening through wetting and drying cycles by rain or irrigation, thereby improving the soil rootability. A leguminous mulch was added in different concentrations to a structurally fragile tropical soil enriched with calcium, which then had different irrigation intervals. The treatments were with or without mulch (10 t/ha), with or without added nitrogen (100 kg/ha at 2 intervals) and two irrigation intervals. In 2015 the irrigation intervals were either 4 or 8 days, and in 2016 they were either 6 or 9 days. Two years were used in the attempt to achieve greater differences, as for tested variables, between treatments. Maize planted in these soil treatments was measured for physiological performance, water use efficiency and yield. Mulch used on structurally fragile tropical soil enriched with calcium was found to delay increased penetration resistance from hardening by wet/dry cycles. In this context, an improved soil rootability led to an enlargement of the leaf area index, greater nitrogen uptake and increased CO2 assimilation. This had important physiological consequences due to the positive effect on increased dry matter production and maize yield. In addition, these results suggested that mulch, used with urea, can delay the water supply for 3 or 4 days due to improvements in soil rootability caused by calcium and organic matter interactions. This may be crucial to a region where small intervals without rain are increasingly common due to global climate change. Therefore, due to a greater water use efficiency, this strategy may be a profitable way to increase crop productivity in tropical conditions rather than increasing water and nutrient application alone.

A field study to optimize the nitrogen (N) top-dressing mode of panicle fertilization and improve rice yields was conducted in mid-eastern China. Japonica cultivar Yunongjing-6 was grown and panicle N fertilizer was applied at the beginning of the inverted fourth leaf stage using three different modes: manual broadcast application (BA) on the soil surface as a control treatment, deep application during ditching at a depth of 15 cm (DD) and manual BA on the soil surface during deep ditching (BAD). The activity of soil enzymes, including invertase, urease, phosphatase and catalase, was increased significantly at the jointing, booting and grain-filling stages with the DD and BAD treatments compared with the traditional BA mode. The DD and BAD treatments also increased basal internode and neck-panicle internode bleeding intensity. The DD treatment gave the highest crop yield, increasing the yield by 0.63 and 0.31 t/hm2 in 2011 and 2012, respectively, compared with BA. The results suggest that ditching during panicle N fertilizer application after sun-drying of the fields increases rice yields, most likely by improving the activity of soil enzymes and enhancing the physiological activity of roots and grain weight.

An indirect method of estimating the heat value of food stuffs, such as milk, is to determine the amounts of fat, sugar, and proteid chemically, and to multiply by the average caloric value of each; but since the amounts of these substances themselves indicate the quality of the milk their calculated caloric value need not be employed as a test of its quality.

1. Experiments were carried out in four seasons at Barberton, South Africa, occupying approximately 2¼ acres of ground. Three soil treatments were used, viz. Normal (N), Compressed (C) and Grubbed (loosened) (G).

2. Measures of consolidation of the soil were made with a specially designed apparatus, and large differences established (pp. 516–520).

3. Estimations of water content and nitrate content were carried out. No great differences were found (pp. 520–524).

4. Fortnightly samples of the plants were taken, from which numerical data were collected designed to estimate morphological development (primary data, pp. 526–529).

5. Derived data on net assimilation rate, relative leaf-growth rate and efficiency index were calculated (pp. 529–533).

6. Growth in total dry weight was found to conform approximately with an exponential law up to the time of flowering. Up to this stage also net assimilation rate was found to remain constant.

7. Growth differences between treatments were related to variation in net assimilation rate only (p. 531).

8. The results were analysed statistically. Significant results alone are emphasized.

9. In all respects growth and development on the consolidated soil was more rapid than that on the grubbed soil, normal being generally intermediate.

10. The results are discussed with reference to the question of nitrogen supply, water supply and aeration of the soil.

The paper reports a laboratory study on miscible displacement of reactive solutes during leaching a highly saline-sodic soil rich in soluble sodium carbonate with solutions of calcium chloride. The effect of varying flow velocities, initial soil moisture content and concentration of calcium in the leaching water on the extent of carbonate precipitation and replacement of sodium by calcium from the exchange positions was studied in soil columns. The results showed that precipitation of soluble carbonates in the soil increased with increasing flow velocity, initial soil moisture content and concentration of calcium in the leaching solution. The results further showed that the calcium exchange capacity of the soil was reduced significantly and nearly proportionally with decrease in the degree of water saturation as a consequence of decreased water application rate and initial soil moisture content. In view of the results obtained, a simple model to describe calcium-sodium exchange under unsaturated flow conditions in saline-sodic soils under consideration has been proposed. Possible implications of the results in actual field situations is discussed.

Variations in floral morphology have been observed by most breeders involved in cowpea (Vigna unguiculata (L.) Walpers) improvement. Usually, the most successful pod set is achieved following hand pollination when plants with large flowers are used as female parents because these are easy to manipulate. In breeding work involving wide crosses, unconscious selection of female parents on the basis of flower size could lead to correlated changes in pod and seed characteristics which may or may not be desirable. This would depend on the heritability of flower size and its correlation with the pod and seed characteristics.

Water buffaloes (Bubalus bubalis) are reared in many tropical and subtropical countries for meat and milk production and to serve as draught animals. The improvement of milk yield in water buffaloes has been handicapped by the absence of physiological data that may provide means of rapid genetic improvement. Endocrine function is known to vary with lactation intensity. Thyroid hormones seem to have a stimulatory effect on the metabolic rate and, consequently, on the productivity of dairy animals (Lenon & Mixner, 1957; Picha, Pichova & Karasek, 1970; Swanson, 1972). Anderson (1969) also reported an increase in thyroid activity in lactating cows and rats, although other investigators (Johnson & Vanjonack, 1976; Hart et al. 1978; Hart, Bines & Morant, 1979) reported that lactation induced a decline in plasma thyroid hormones. None of these studies performed measurement of plasma thyroid stimulating hormone.

An observed positive correlation between tuber sprout growth in store and yield and tuber weight was due to the association of short sprouts with small tubers (less than 75 g). Sprout growth in larger tubers appears to be unaffected by tuber weight.

The objective of this work was to evaluate the effect of protein reduction, with or without the supplementation of limiting amino acids, on the performance and carcass characteristics of meat quails from 22 to 42 days of age in a thermoneutral environment. A total of 324 European quails were randomly allocated into nine diets. The diets were formulated based on the recommended requirement (control) and were differentiated according to crude protein (CP) reduction levels into moderate reduction (10%) and severe reduction (20%). The diets were supplemented or not with limiting amino acids. The diets with severe and moderate protein reduction meeting the methionine + cystine, lysine and threonine requirements led to weight gain equivalent to that of the control quails. The diet with a moderate reduction in CP, with or without meeting the methionine + cystine requirement or meeting the methionine + cystine and lysine requirement, led to the greatest carcass yield and a greater leg weight and were similar to the control treatment. It is observed that supplementation with the crystalline sources of the amino acids is able to improve the performance of the quails, in addition, the attendance of methionine + cystine requirement important factor when the CP levels are reduced. In our studies, diets with 17.5% CP and supplemented with methionine + cystine, lysine and threonine meet the requirements of quails, thus generating a limiting amino acid requirement, so they are recommended for meat quails from 22 to 42 days old housed in thermoneutral environment.

It is estimated that only 35–50% of the potential yield of field lettuce crops is harvested (Gray, 1978c). A major contributory factor is the failure to establish full, uniform plant stands. Erratic lettuce emergence has been attributed to inadequate soil moisture, soil crusting, and high (> 25 °C) soil temperature (Hemphill, 1982).

1. The effect of four different planes of nutrition of lambs until they reach 30 1b. dressed carcass weight on the development of the form of the ribs is studied.

2. The growth in length of the ribs is found to be more influenced by age and less by the plane of nutrition than their growth in thickness, and is not reflected in the weight of the ribs.

It is often stated that organic rice has a higher content of healthy phytochemicals than ordinary rice, and the facts on this claim obtained experimentally are rare. Riceberry is a new rice variety in Thailand. This study aimed to evaluate the effects of organic practice and conventional practice on the content of chemical composition and bioactive compounds in Riceberry rice. The results showed that agricultural practices were not significantly different for grain yield in the first year, but they were different in the second year. Rice produced by organic practice had a higher content of iron, gamma-aminobutyric acid, total phenolic and anthocyanin (4.15, 1.67, 41.3 and 20.1 mg/100 g dry weight in the first year, and 4.06, 3.37, 89.7 and 14.7 mg/100 g dry weight in the second year) than that produced by conventional practice (2.25, 1.11, 38.8 and 6.89 mg/100 g dry in the first year, and 1.96, 2.77, 54.1 and 5.71 mg/100 g dry in the second year). Rice produced by organic practice also had lower sugar content (2.92 g/100 g dry weight in the first year, and 1.99 g/100 g dry weight in the second year) than that produced by conventional practice (3.46 g/100 g dry weight in the first year, and 2.81 g/100 g dry weight in the second year). Gamma oryzanol and antioxidant capacity were also lower in organic rice compared to conventional rice. This study indicated that organic Riceberry rice had a higher quality compared to non-organic rice.

1. Inaccurate results previously obtained with wet-combustion methods for the determination of carbon in soils have probably been due to: (a) incomplete oxidation of carbon; (b) incomplete absorption of carbon dioxide. The method described herein ensures complete oxidation and complete absorption. The oxidizing agent employed consists of a mixture of sulphuric acid and potassium bichromate; the absorption takes place in a closed system.

2. When highly accurate results are required, a combustion tube is a necessary adjunct to the wet-combustion method, as appreciable amounts of carbon escape complete oxidation in reaction flask.

3. The soil should be moistened with water before adding the oxidizing mixture, to avoid the formation of complexes, which may protect part of the carbon from oxidation by the acid.

4. Within limits, the concentrations of sulphuric acid and potassium bichromate do not affect the results.

5. While it is necessary to use catalysts (selenium and potassium sulphate) for the complete oxidation of the resistant carbon of coal, catalysts were found to be unnecessary for the determination of carbon in soils.

6. For soils rich in chloride, it is necessary to absorb the chlorine evolved by means of sodium bisulphite solution.

1. An accurate method of estimating the density of spermatozoa in a suspension by the haemocytometer is described.

2. A rapid method of estimating the density of a semen sample by the use of Brown's opacity tubes is given. There is a simple linear relation between opacity and density, the latter expressed in terms of millions of spermatozoa per ml. being approximately five times the opacity standard.

3. The rapid method is sufficiently accurate for use in insemination centres.

Colchicine induced 64-chromosome white clover was compared at a number of centres with control material (2n = 32), as spaced plants and in broadcast plots with and without companion grasses.

The chromosome-doubled material generally conformed to the well-known reaction of polyploids; the plants were later flowering, had thicker petioles and stolons, broader leaflets and spread less vigorously. Yield of green matter of spaced plants was much less, and in broadcast plots the gross yield (grass + clover) and that of the clover fraction was 7% less than in comparable S. 100 plots. The Finlay-Wilkinson analysis indicated that the chromosome-doubled form did not respond to improved conditions to the same extent as did the control varieties. The presence of grass in the mixture partly compensated for low clover yield, but was insufficient to increase total yields to that of S. 100 controls.