Do photosynthetic metabolism and habitat influence foliar water uptake in orchids?

Epiphytic and rupicolous plants inhabit environments with limited water resources. Such plants commonly use Crassulacean Acid Metabolism (CAM), a photosynthetic pathway that accumulates organic acids in cell vacuoles at night, so reducing their leaf water potential and favouring water absorption. Foliar water uptake (FWU) aids plant survival during drought events in environments with high water deficits. We hypothesized that FWU represents a strategy employed by epiphytic and rupicolous orchids for water acquisition and that CAM will favour increased water absorption. We examined 6 epiphyte, 4 terrestrial and 6 rupicolous orchids that use C3 (n = 9) or CAM (n = 7) pathways. Five individuals per species were used to evaluate FWU, structural characteristics and leaf water balance. Rupicolous species with C3 metabolism had higher FWU than other species. FWU (Cmax and k) could be related to succulence, SLM and leaf RWC. The results indicated that high orchid leaf densities favoured FWU, as area available for water storage increases with leaf density. Structural characteristics linked to water storage (e.g. high RWC, succulence), on the other hand, could limit leaf water absorption by favouring high internal leaf water potentials. Epiphytic, rupicolous and terrestrial orchids showed FWU. Rupicolous species had high levels of FWU, probably through absorption from mist. However, succulence in plants with CAM appears to mitigate FWU.

Microencapsulated and uncoated butyric acid as alternative additives to the regeneration of intestinal mucosa in broilers challenged with Eimeria spp.

1. The effect of microencapsulated and uncoated butyric acid as an alternative to antibiotics on performance, intestinal morphology and regeneration of intestinal mucosa was studied in birds experimentally infected with Eimeria spp. 1 to 42 d-old.2. A total of 1,320 male Cobb® broiler chicks were allocated to one of five treatments in a completely randomised design, comprising a negative control, uncoated butyric acid (UA), microencapsulated butyric acid (MA), combined U + M butyric acid and a positive control (antibiotic+anticoccidial) in six replications. At 16 d-old, the birds were inoculated orally with 0.5 ml of a solution containing an Eimeria spp. pool.3. At 21 d of age, the birds receiving butyric acid alone had higher body weight gain (BWG) and feed intake (FI) compared to those supplemented with the blend of acids. For the total rearing period, in all variables, the positive control performed best (P < 0.001).4. At 14 d of age, birds that received diets containing UA had a deeper crypt depth in the jejunum than those fed diets containing microencapsulated acid (P = 0.0194). At 21 d of age, the birds fed the acids had higher villi (P = 0.0058) in the duodenum, compared to the negative control group.5. Supplementation with microencapsulated acid contributed to the intestinal health and recovery of post-challenge birds, but did not result in improvements in performance.

Standardization of A Sample-Processing Methodology for Stable Isotope Studies in Poultry

The objective of this study was to determine if lipid extraction processes alter the isotopic value of 13C and 15N of tissues (pectoral muscle, thigh and liver) and eggs and if the use of anticoagulants interferes with blood and plasma 13C and 15N isotopic values. Samples were acquired from the same flock of birds. The 32 egg samples were randomly divided into four treatments (liquid, dehydrated, and fat-extracted with ether or chloroform + methanol) with eight replicates each. The 24 samples of pectoral muscle, thigh muscle and liver of broilers were randomly divided into three treatments (dehydrated, fat-extracted with ether and chloroform + methanol) with eight replicates each. Blood samples were divided into a 3x3 factorial arrangement with three physical forms (liquid, oven-dried or freeze-dried) and three collection methods (with no anticoagulant, with EDTA or heparin). Plasma samples were distributed in a 3x2 factorial arrangement, with three physical forms (liquid, oven-dried, or freeze-dried) and two anticoagulants (EDTA or heparin). The obtained isotopic results were submitted to the multivariate analysis of variance (MANOVA) and univariate (ANOVA, complemented by Tukey test), using the GLM procedure of the statistical program SAS (1996) or Minitab 16. The results show that it is possible to use the evaluated methods of fat extraction, drying and anticoagulants in the isotopic analyses of carbon-13 and nitrogen-15 in chicken tissues.(AU)

Standardization of A Sample-Processing Methodology for Stable Isotope Studies in Poultry

The objective of this study was to determine if lipid extraction processes alter the isotopic value of 13C and 15N of tissues (pectoral muscle, thigh and liver) and eggs and if the use of anticoagulants interferes with blood and plasma 13C and 15N isotopic values. Samples were acquired from the same flock of birds. The 32 egg samples were randomly divided into four treatments (liquid, dehydrated, and fat-extracted with ether or chloroform + methanol) with eight replicates each. The 24 samples of pectoral muscle, thigh muscle and liver of broilers were randomly divided into three treatments (dehydrated, fat-extracted with ether and chloroform + methanol) with eight replicates each. Blood samples were divided into a 3x3 factorial arrangement with three physical forms (liquid, oven-dried or freeze-dried) and three collection methods (with no anticoagulant, with EDTA or heparin). Plasma samples were distributed in a 3x2 factorial arrangement, with three physical forms (liquid, oven-dried, or freeze-dried) and two anticoagulants (EDTA or heparin). The obtained isotopic results were submitted to the multivariate analysis of variance (MANOVA) and univariate (ANOVA, complemented by Tukey test), using the GLM procedure of the statistical program SAS (1996) or Minitab 16. The results show that it is possible to use the evaluated methods of fat extraction, drying and anticoagulants in the isotopic analyses of carbon-13 and nitrogen-15 in chicken tissues.

Modelling and determination of metabolic pools by stable carbon isotopes in the avian duodenal mucosa and albumen.

Stable isotope analyses have helped in assessing dietary switches if the diet undergoes metabolic alteration (isotopic exchange). However, when considering the effects over time of switching from one diet to another, one can assess how quickly the new diet is incorporated into tissues via the isotopic renewal or incorporation rate, or turnover. Turnover is obtained using exponential curves that fit the original data, allowing the determination of practical order parameters such as the half-life (T) and the turnover constant (k). Researchers have found that metabolic incorporation can be fractionated. The resulting fractions, called metabolic pools, are identified using the linearization of the isotopic exchange model and its linear fit. This fractionation methodology is still not well defined. The objective of this study was to assess the behaviour of the metabolic renewal rate (turnover) in fractionated form, explain the theory, and apply it to data from the avian duodenal mucosa and albumen. We concluded that the duodenal mucosa has one metabolic pool, with a half-life of 1.23 days, and that the albumen has two metabolic pools, with half-lives of 1.89 and 6.32 days.