The effects of extraction techniques and quantitative determination of oxalates in Nerium oleander and feeds.

Shrubs represent the most affordable and accessible form of feed that livestock can rely on to acquire both essential and non-essential elements of life. In addition to their inherent toxins, they contain endogenous substances commonly referred to as 'antinutritive factors' (ANFs) that often interfere with the utilisation of nutrients. Their abundance may lead to severe clinical trauma. Hence, the objective of the study was to investigate the effects of different extraction techniques on Nerium oleander L. and animal feeds as well as to quantify oxalates. Organic (hexane, acetone and methanol) sequential and aqueous (infusion and decoction) extractions were explored. Qualitative and quantitative analyses were conducted to determine the presence of various phytochemicals and oxalate contents as putative ANFs, respectively. The results showed higher extraction yields of 22.6% and 43.1% in the decoction and infusion of N. oleander, respectively. The quantification methods were validated for linearity, accuracy and precision. Oxalate contents of 6.76 ± 0.245 (0.65%) mg/g and 5.74 ± 0.236 mg/g dry weight (0.55%) were obtained in N. oleander and feeds, respectively. This difference was statistically significant with p < 0.05. Percentage recoveries of 98.5 (percent relative standard deviation [% RSD] = 2.3), 85.7 (% RSD = 1.03) and 80.3 (% RSD = 1.22) at 76%, 95% and 112% fortifications were obtained, respectively. Relative standard deviation for precision was 0.99% and 1.13% at 0.33 mg and 0.39 mg fortifications, respectively, while reproducibility showed 2.21% RSD. Therefore, these methods can be used to provide a valuable basis for qualitative determination of ANFs, particularly in shrub foliage.

Variability of amino acid digestibility of lupin and pea grains in caecectomised laying hens.

1. The objective of this study was to investigate the variations in amino acid (AA) digestibility of lupin and pea grains in caecectomised laying hens. The relationship between AA digestibility and chemical constituents of the grains was determined. 2. Twelve variants of lupins and peas were each added to a basal diet at a concentration of 300 g/kg, at the expense of maize starch. The lupin and pea variants were separately investigated in two subsequent trials. Each trial consisted of two 7 × 7 Latin squares, each comprising the basal diet and six diets with lupins or peas. 3. Fourteen caecectomised laying hens (LSL-classic) were individually housed in metabolism cages and 120 g/d of experimental diets were provided for eight days. During the last four days, excreta were collected quantitatively and feed intake was recorded. A regression approach was used to determine the AA digestibility of the lupin and pea variants. 4. Amino acid digestibility of the lupins and peas was high, although significant differences in AA digestibility among the lupins and peas were detected. The digestibility of lysine was in the range of 0.87-0.91 and 0.87-0.93 for lupins and peas, respectively. The digestibility of methionine in lupins and peas varied between 0.80-0.88 and 0.72-0.90. Variations in AA digestibility in peas were more pronounced than in lupins. 5. Significant correlations between chemical constituents of lupins, such as alkaloids, and AA digestibility were detected in some cases, without a consistent pattern. In peas, tannin concentration and the insoluble protein fraction were negatively correlated with digestibility of some AAs, but only when one colour flower variant was considered. Trypsin inhibitor activity in peas was negatively correlated with AA digestibility, particularly for the white flower variants.

Efectos del tostado sobre el valor de energía metabolizable verdadera y el contenido de factores antinutricionales de harinas de granos / De canavalia ensiformis (l.) Effects of toasting on true metabolizable energy value and content of antinutritional factors of canavalia ensiformis (l.) Seed meals

El efecto del tostado sobre el valor de energía metabolizable verdadera corregida para balance de nitrógeno nulo (EMVn) y el contenido de factores antinutricionales (FAN) de harinas tostadas de Canavalia fue investigado en un ensayo de balance. Adicionalmente, se determinó el contenido de lisina reactiva, la solubilidad de la proteína y el color en las harinas evaluadas. Se asignaron al azar 5 gallos cecotomizados a cada harina (cruda o tostada) a las siguientes temperaturas y tiempos: 180; 200; 220; and 230°C/3 min; 230 y 240°C/2 min; 230 y 240°C/1 min. Cada gallo fue intubado con 40g de harina y las heces fueron recolectadas durante 72 horas. La Concanavalina A (Con A) en las harinas tostadas fue detectada determinando la unión de esta lectina a la mucosa duodenal por inmunohistoquímica. Ninguna de las harinas tostadas mostró actividad hemaglutinante de la Con A, pero se observó unión de esta lectina a la mucosa duodenal con una reacción inmunohistoquímica de moderada a débil. El tostado a 220; 230°C/3 min ó 240°C/2 min redujo la canavanina en más del 90% en relación con la harina cruda. No se observaron diferencias significativas (P < 0,05) entre el valor de EMVn de la harina cruda y el de las harinas tostadas a 200; 220; 230°C/3 min; 240°C/1 ó 240°C/2min mientras que, el tostado a 180°C/3min; 230°C/1min ó 230°C/2min redujo significativamente (P < 0,05) la EMVn. La lisina reactiva y la solubilidad de la proteína fueron reducidas (P < 0,05) al aumentar la temperatura y el tiempo de tostado. El color de las harinas fue también afectado (P < 0,05) por el tostado. En conclusión, el tostado bajo las condiciones evaluadas, puede reducir significativamente el contenido de FAN de la harina cruda de Canavalia. Sin embargo, esta respuesta positiva no incrementó el valor de EMVn de la harina cruda.

The effects of toasting on the True Metabolizable Energy, corrected to zero nitrogen retention (TMEn) and content of antinutritive factors (ANF) present in Jack Beans (JB, Canavalia ensiformis) seeds were investigated in a balance trial. Reactive lysine, protein solubility, and color were also determined in experimental meals. Raw JB meal was toasted at the following combinations of temperature and time: 180; 200; 220 and 230°C/3min; 230 and 240°C/2min; and 230 and 240°C/1min. Five caecectomised cockerels were randomly assigned to each JB meal (raw or toasted). Each bird was intubated 40g of a given meal and excreta were quantitatively collected during 72h. Concanavalin A binding to duodenal mucosa was assessed by immunohistochemistry. No hemaglutinating activity was detected in toasted JB but Con A binding to duodenal mucosa ranged from moderate to weak. Toasting JB meal at 220; 230°C/3min; and 240°C/2min reduced the original canavanine content of JB in more than 90%. TMEn value of raw JB was not improved by toasting. No significant differences were found between TMEn of raw JB and those of JB toasted at 200; 220; 230°C/3min; 240°C/1min or 240°C/2min, whereas toasting JB meal at 180°C/3min; 230°C/1min or 230°C/2min significantly (P < 0.05) reduced TMEn. Reactive lysine and protein solubility were reduced (P < 0.05) as both temperature and toasting time increased. Meal color was also affected (P < 0.05) by toasting. In summary, under the conditions tested, toasting can effectively reduce ANF content in raw JB. However, this positive response did not improve the TMEn value of raw JB.