Gross Energy Levels Research Articles

Rice gluten meal as a substitute for soybean meal in the diets for growing rabbits

ABSTRACT The impacts of different dietary levels of rice gluten meal (RGM) on growth performance, digestibility, carcass characteristics, and blood traits of growing New Zealand White (NZW) rabbits were studied. One hundred and twenty, 6 weeks old weaned male rabbits (body weight; 682 [g] ± 23) were randomly allotted into four groups. The control diet contained 160 [g/kg] soybean meal (SBM), while the other three diets were obtained by replacing 40, 80, and 120 [g/kg] SBM with RGM (RGM40, RGM80, and RGM120, respectively). The results showed that RGM contained higher levels of dry matter (DM), crude protein (CP), ether extract (EE), ash, and gross energy than SBM. RGM contained a high level of arginine followed by leucine and valine as essential amino acids and high levels of glutamic, aspartic acid, and alanine as non-essential amino acids. The obtained results showed that the final body weight of rabbits fed diets containing 40, 80, and 120 [g/kg] RGM was higher than those fed the control diet. The daily weight gain of rabbits fed RGM diets increased (p < 0.05) by 10.50%, 6.50%, and 10.00%, respectively, compared to the control group. Rabbits fed RGM80 showed the highest (p < 0.05) digestibility of DM, organic matter (OM), EE, neutral detergent fibre (NDF), and acid detergent fibre (ADF) compared to the other tested levels. Rabbits fed RGM120 had the highest (p < 0.05) digestible energy (DE) and digestible crude protein (DCP) values. RGM inclusion levels of 40 and 80 [g/kg] increased (p < 0.05) plasma total protein and albumin compared to the control group. Rabbits fed a diet containing RGM40 had the highest (p < 0.05) globulin level. The highest (p < 0.05) plasma urea concentration level was measured in the rabbit group fed the RGM120 diet. Conclusively, RGM could be a valuable ingredient for growing rabbits, as at all the tested levels improved growth performance, digestibility, and nutritional values.

Effects of Dietary Protein-to-Energy Ratios on Growth, Immune Response, Antioxidative Capacity, Liver and Intestinal Histology, and Growth-Related Gene Expression in Hybrid Yellow Catfish (Pelteobagrus fulvidraco ♀ × Pelteobagrus vachelli ♂).

This study is aimed at evaluating the effects of dietary protein-to-energy ratios on the growth, immunological response, antioxidative capacity, liver and intestinal histology, and growth-related gene expression of hybrid yellow catfish (Pelteobagrus fulvidraco ♀ × Pelteobagrus vachelli ♂). Eight diets were formulated to form different protein/energy ratios of 84, 88, 90, 93, 95, 96, 99, and 103 mg/kcal (P/E84, P/E88, P/E90, P/E93, P/E95, P/E96, P/E99, and P/E103), respectively. These diets contain different levels of gross energy (GE), ranging from 4.13 to 4.76 kcal g-1. Seven hundred and twenty healthy fish (17.15 ± 0.02 g) were randomly dispersed into 24 rectangular fiberglass tanks with 8 treatments in triplicate groups. The fish fed a P/E ratio of 95 mg/kcal demonstrated the best growth and feed utilization. A significant (P < 0.05) increase in percent weight gain (WG%) and specific growth rate (SGR) was seen as the dietary P/E ratio ameliorated from P/E84 to P/E95, followed by a decreased pattern in these parameters. Feed conversion ratio (FCR) and daily feed intake (DFI) were significantly impacted by dietary P/E ratios (P < 0.05). Additionally, an optimum P/E ratio improved intestinal morphology. However, low or high P/E ratio diets can cause oxidative stress, impaired liver function, and significantly reduced nonspecific immunity. The expression of target of rapamycin (TOR) and insulin-like growth factor-1 (IGF1) genes in the liver was considerably influenced by dietary protein-to-energy ratios (P < 0.05). Based on the statistical analysis of WG% against the dietary P/E ratio, the optimal P/E ratio for the studied species was estimated to be 92.92 mg/kcal.

Zeolite and corn with different compositions in broiler chickens feeding

The objective of this work was to evaluate the behavior of zeolite against different types of corn in broiler chickens' diets. 1,200 male broiler chickens were assigned to 6 diets in a completely randomized design and a 2×3 factorial arrangement, consisting of 2 types of corn (higher or lower mycotoxin contamination) and the inclusion of zeolite (0; 5,000 and 10,000 g ton-1). In the period from d 1 to 21, there was an interaction (P=0.0040) between types of corn and the inclusion of zeolite for feed conversion ratio (FCR). In the phase from 1 to 42 d, there was an interaction (P=0.0322) on the serum levels of creatinine (CREA) and digestible gross energy (dGE); corn with lower mycotoxin level contamination (LMLC), caused a reduction in body weight gain (BWG) (P=0.0046) and increase in the relative weight of abdominal fat (P=0.0256). Inclusion rates of zeolite promoted an increase in the digestible CP (P=0.0477) and digestible ash (P < 0.0001), as well as an increase (P < 0.0001) in hot carcass yield (P=0.0433). The results indicate that the inclusion of zeolite, in the amounts used, did not alter the performance, serum levels, intestinal development and litter quality of the birds at 42 d of age. However, it was responsible for the improvement in the percentage of digestible nutrients (CP, GE, and MM).

Effects of different processing techniques of broken rice on processing quality of pellet feed, nutrient digestibility, and gut microbiota of weaned piglets.

The present study was conducted to assess the effect of different processing techniques of broken rice on processing quality of pellet feed, growth performance, nutrient digestibility, blood biochemical parameters, and fecal microbiota of weaned piglets. A total of 400 crossbred piglets (Duroc × Landrace × Yorkshire) with a mean initial body weight (BW) of 7.24 ± 0.52 kg were used in a 28-d experiment. Piglets were randomly distributed to one of 4 treatment and 10 replicate pens per treatment, with 10 piglets per pen. The dietary treatments were as follows: CON, corn as the main cereal type in the dietary; BR, 70% of the corn replaced by broken rice; ETBR, 70% of the corn replaced by extruded broken rice; EPBR, 70% of the corn replaced by expanded broken rice. Extruded broken rice and expanded broken rice supplementation significantly (P < 0.05) increased hardness, pellet durability index, crispness, and starch gelatinization degree. Extruded broken rice and expanded broken rice generated a higher (P < 0.05) average daily feed intake, increased (P < 0.05) average daily gain, decreased (P < 0.05) feed conversion ratio, and lowered (P < 0.05) the diarrhea rate. Piglets fed extruded broken rice displayed high apparent total tract digestibility levels of dry matter (P < 0.05), gross energy (P < 0.05), crude protein (P < 0.05), and organic matter (P < 0.05). In addition, extruded broken rice and expanded broken rice supplementation had increased Lactobacillus and Bifidobacterium levels in gut, whereas a lower abundance of the potential pathogens Clostridium_sensu_strictio_1 and Streptococcus was observed. Dietary supplementation of extruded broken rice and expanded broken rice failed to show significant effects on blood biochemical parameters. Combined, 70% corn substituted with broken rice failed to show significant effects. Collectively, extruded broken rice and expanded broken rice supplementation had positively enhanced the pellet quality, growth performance, nutrient digestibility, and gut microbiota of weaned piglets.

Nutrient Composition and In Vitro Fermentation Characteristics of Sorghum Depending on Variety and Year of Cultivation in Northern Italy

Sorghum is the fifth most produced cereal in the world and is a source of nutrients and bioactive compounds for the human diet. This study examined the nutrient composition and in vitro fermentation characteristics of sorghum varieties grown in 2020 and 2021 (n = 15 × 3 × 2) across three locations in the north of Italy (Bologna, Padova, and Rovigo). In 2020, the crude protein content of sorghum was significantly higher in the region of Padova than in the region of Bologna (124 vs. 95.5 g/kg dry matter). However, crude fat, sugar, and gross energy levels showed no significant differences among the different regions in 2020. In 2021, the levels of crude protein, crude fat, sugar, and gross energy had no significant differences among different sorghum varieties harvested from the three regions. Significant differences in some mineral contents were found among the samples particularly in manganese and zinc in both years. After 24 h of fermentation of two different sorghum hybrids (hybrids 1 and 2 of both years harvested in Bologna, n = 4 × 2 × 2), the pH value was significantly higher in hybrid 1 of year 2021 (3.98) than in the other fermented samples (range: 3.71–3.88). The sorghum harvested from the region of Bologna had a significantly higher viscosity value (1.22 mPa·s) compared to other regions (1.8–1.10 mPa·s) in 2021 only. The results show that the nutritional value and viscosity of different sorghum varieties could differ depending on the location and year of cultivation.

Effect of boiling and roasting on physicochemical and antioxidant properties of dark red kidney bean (Phaseolus vulgaris)

The effects of two processing methods (boiling and roasting) on physicochemical qualities of dark red kidney bean (Phaseolus vulgaris) were investigated. Changes in total polyphenol content (TPC) and antioxidant activity due to processing were also analyzed by using Folin–Ciocaltue method and 1,1 diphenyl-2-picrylhydrazyl (DPPH) assay, respectively. Analysis of physicochemical properties exhibited substantial variations (p&lt;0.05) in the levels of moisture, ash, protein, fat, carbohydrate, gross energy and pH of raw and processed beans. Meanwhile, there was no considerable difference (p&lt;0.05) in the fibre content of fresh and processed beans. Investigation of total phenolic content showed the significant (p&lt;0.05) reduction of phenolic compounds in boiled (5.53±0.74 mg GAE/ g) and roasted (8.15±1.60 mg GAE/g) beans than raw samples (12.55±1.42 mg GAE/g). DPPH radical scavenging activity was also decreased significantly (p&lt;0.05) in boiled and roasted samples with IC50 value of 0.0608±0.0765 mg/mL and 0.0523±0.0026 mg/mL, respectively. In the case of household cooking, keeping boiling water would be advised for the preservation of minerals, vitamins and phenolic compounds. The roasting process may be used to develop high-quality health-promoting dark red kidney bean products.

A study: nutrient content evaluation of dried poultry waste urea molasses block (dpw-umb) on proximate analysis

The research purpose was to determine the nutrient content of dried poultry waste molasses block (DPW-UMB). The use of dried poultry waste in the manufacture of the urea-molasses block was as a substitute of urea and could improve the value added in dry season. The treatments used for research were T 1 (15% manure layer chicken and 25% molasses), T 2 (10% manure layer chicken and 30% molasses), and T 3 (20% manure layer chicken and 30% molasses). Chemical analysis: the dried of poultry waste were analyzed for dry matter, crude protein, crude fiber, ash, fat, and gross energy. The statistical formulation diet composed of Microsoft Excel Ver. 2016. The results showed that the 20% manure layer chicken and 30% molasses (T 3 ) were better than T 2 and T 1 on nutrient content with 92.04% Dry Matter (DM), 13.34% Crude Protein (CP), 13.39% Crude Fiber (CF), 37.16% ash, 3.44% fat, but low in Gross Energy (GE) (2631.63 kcal/kg). It could be concluded that dpw-umb T3 were dried of poultry waste contained sufficient levels of gross energy, crude protein, crude fiber, ash, and fat it could be used as feedstuff for ruminants for supplementation with the required nutrients.

Effects of Processing (Boiling and Roasting) on the Nutritional and Antinutritional Properties of Bambara Groundnuts (Vigna subterranea [L.] Verdc.) from Southern Kaduna, Nigeria

This research analyzed the effect of processing (boiling and roasting) on the proximate, antinutrient, and mineral composition of Vigna subterranea seeds. The proximate composition analysis showed significant difference (P&lt;0.05) between the levels of crude lipid, crude fiber, gross energy, carbohydrate, and moisture content in the raw and processed V. subterranea. However, no significant difference (P&lt;0.05) was observed in protein content of processed V. subterranea as compared to the raw seeds. Analyses of antinutrient composition show that processing significantly reduced the levels of oxalate, tannins, phytate, trypsin inhibitor, and hydrogen cyanide contents of V. subterranea. While magnesium, potassium, and phosphorus were the most abundant macrominerals in V. subterranea, zinc was the most abundant micromineral. Correlation analysis revealed that the levels of crude protein, ash, moisture, and lipid were negatively affected by phytate, tannins, and oxalate. The results, therefore, suggest that processing significantly lowered the levels of antinutrients in V. subterranea, thereby making it safer for consumption.

Proximate, Antinutrients and Mineral Composition of Raw and Processed (Boiled and Roasted) Sphenostylis stenocarpa Seeds from Southern Kaduna, Northwest Nigeria.

This research was aimed at evaluating the proximate composition, level of anti-nutrients, and the mineral composition of raw and processed Sphenostylis stenocarpa seeds and at examining the effect of processing on the parameters. From the proximate composition analysis, the ash content showed no significant difference (P > 0.05) between the processed and unprocessed (raw) samples. However, there was significant difference (P < 0.05) in the levels of moisture, crude lipid, nitrogen-free extract, gross energy, true protein, and crude fiber between the processed and unprocessed S. stenocarpa. Analyses of the antinutrient composition show that the processed S. stenocarpa registered significant reduction in levels of hydrogen cyanide, trypsin inhibitor, phytate, oxalate, and tannins compared to the unprocessed. Evaluation of the mineral composition showed that the level of sodium, calcium, and potassium was high in both the processed and unprocessed sample (150–400 mg/100 g). However, the level of iron, copper, zinc, and magnesium was low in both processed and unprocessed samples (2–45 mg/100 g). The correlation analysis showed that tannins and oxalate affected the levels of ash and nitrogen-free extract of processed and unprocessed seeds. These results suggest that the consumption of S. stenocarpa will go a long way in reducing the level of malnutrition in northern Nigeria.

Sweet Potato-Based Complementary Food for Infants in Low-Income Countries

In low-income countries, most infants are given cereal-based complementary foods prepared at the household level. Such foods are high in phytate, which limits the bioavailability of nutrients, including iron, calcium, zinc, and in some cases proteins, which are crucial to the development of infants. To compare the levels of macronutrients (protein, fat, and carbohydrate), gross energy, and fructose in sweet potato-based (denoted ComFa) formulations and enriched Weanimix (dehulled maize-dehulled soybean-groundnut blend with fish powder and sugar incorporated). The phytate level was also compared. A composite flour of sweet potato and soybeans containing fish powder was processed by oven toasting as a home-based complementary food. Another blend containing skim milk powder was processed by extrusion cooking or roller drying as industrial-based prototypes. The macronutrient composition and the levels of fructose and phytate were determined in the ComFa formulations and enriched Weanimix. The ComFa formulations and the enriched Weanimix met the stipulated values in the Codex Alimentarius Commission standard for energy (400 kcal/100 g), protein (15 g/100 g), and fat (10 to 25 g/100 g) for complementary food, with the exception of the industrial-based ComFa formulations, which satisfied 83% of the protein requirement (15 g/100 g). The ComFa formulations had a quarter of the phytate level of enriched Weanimix. The fructose level in the sweet potato-based complementary foods was more than five times that in enriched Weanimix. The sweet potato-based formulations were superior to enriched Weanimix as complementary foods for infants in low-income countries, based on the fructose (which makes the porridge naturally sweet) and phytate levels.

Requerimientos de proteína y energía bruta en juveniles de camarón rosado Farfantepenaeus paulensis (Pérez-Farfante, 1967) sometidos a diferentes salinidades

The requirement of gross protein and energy and the optimal ratio of these in practical diets for pink shrimp (Farfantepenaeus paulensis) juveniles in different salinities were determined. Shrimp with a mean initial weight of 0.353 g were stocked in 54 plastic tanks at initial densities of 40 ind m -2 . The experiment was factorial, with three levels of gross protein (24, 35, 48%), three levels of salinities (10, 20, 30 psu), and two levels of gross energy (3200, 4200 kcal kg -1 ); the experiment lasted 25 days and considered three replicates. The results showed that salinity and protein had a significant effect (P < 0.05) on weight gain and the specific growth rate, but did not influence on survival. The energy had no significant effect on survival, growth rate, or weight gain. The response of the shrimp to the gross energy and protein level showed different requirements according to the different salinities tested. At salinity of 10 psu, the adequate level was 35% gross protein and 4200 kcal kg -1 (83.3 mg PB kcal -1 ), whereas at salinities of 20 and 30 psu, levels of 24% gross protein and 3200 kcal kg -1 (75.0 mg PB kcal

Requerimientos de proteina y energia bruta en juveniles de camaron rosado Farfantepenaeus paulensis (Perez Farfante, 1967) sometidos a diferentes salinidades

The requirement of gross protein and energy and the optimal ratio of these in practical diets for pink shrimp ( Farfantepenaeus paulensis ) juveniles in different salinities were determined. Shrimp with a mean initial weight of 0.353 g were stocked in 54 plastic tanks at initial densities of 40 ind m -2 . The experiment was factorial, with three levels of gross protein (24, 35, 48%), three levels of salinities (10, 20, 30 psu), and two levels of gross energy (3200, 4200 kcal kg -1 ); the experiment lasted 25 days and considered three replicates. The results showed that salinity and protein had a significant effect ( P < 0.05) on weight gain and the specific growth rate, but did not influence on survival. The energy had no significant effect on survival, growth rate, or weight gain. The response of the shrimp to the gross energy and protein level showed different requirements according to the different salinities tested. At salinity of 10 psu, the adequate level was 35% gross protein and 4200 kcal kg -1 (83.3 mg PB kcal -1 ), whereas at salinities of 20 and 30 psu, levels of 24% gross protein and 3200 kcal kg -1 (75.0 mg PB kcal -1 ) were appropriate.

Dietary protein requirement of juvenile marbled spinefoot rabbitfish Siganus rivulatus

Rabbitfish are an Indo-Pacific herbivorous marine fish that have good market demand and are suitable for aquaculture. The present work was performed to determine dietary protein inclusion necessary for optimal growth of juvenile rabbitfish Siganus rivulatus. Six diets with increasing levels of protein (10, 20, 30, 40, 50 and 60 g crude protein 100 g−1 feed) and similar levels of gross energy (20 MJ kg−1) were prepared and offered to S. rivulatus juveniles maintained in triplicate cages placed in two large water tanks for 49 days. Growth progressively improved with dietary protein for fish offered diets from 10% to 40% protein inclusion. Diets with greater protein levels did not improve fish growth beyond that observed in the 40% group. Daily feed intake, apparent protein utilization and feed conversion ratio decreased as dietary protein increased. Protein efficiency (PE) was greatest (1.47) in fish offered the 10% protein diet and least in fish offered the 60% protein diet (0.80). No differences in PE were observed among all other treatments (20–50%). Results of the present work suggest that minimum dietary requirement for suitable growth of S. rivulatus juveniles is 40% protein when digestible energy of the diet is 16–18 MJ kg−1.

Effects of supplementing two species of marine algae or their fractions to a formulated diet on growth, survival and composition of shrimp ( Litopenaeus vannamei)

Experimental diets were processed by supplementing either whole algae or algae fractions to a formulated control diet to test their effects on growth, survival and composition of juvenile shrimp ( Litopenaeus vannamei). Diatom ( Thalassiosira weissflogii) and Nannochloropsis cultures were freeze-dried and partially extracted with acetone into a carotenoid fraction and a residue fraction. Seven diets were prepared by individually adding whole diatoms ( T. weissflogii), whole Nannochloropsis, a combination of the whole diatoms and Nannochloropsis, their carotenoid fraction, or their residue fraction, to a control diet. After the eight-week feeding trial, shrimp fed diets containing either the whole diatoms, whole Nannochloropsis, a combination of the two, or their residue fractions, achieved higher ( P < 0.05) growth (0.57 to 0.64 g week − 1 ) and survival rates (93.8 to 100%) than those fed the control diet (0.46 g week − 1 ; 79.2%). This enhanced growth effect might not be attributable to the macronutrient composition of the microalgae, because their addition reduced the levels of crude protein, crude lipid, and gross energy in the control diet. The growth rate of shrimp fed diets containing the carotenoid fraction of the diatoms and Nannochloropsis (0.54 and 0.47 g week − 1 ) was similar ( P > 0.05) to that of shrimp fed the control diet. The addition of whole algae also increased the fatty acid and astaxanthin contents of shrimp tail muscles. The improved growth rates indicate the potential advantages of using dried algae as a feed additive, and the benefits of developing phytoplankton in shrimp ponds.

Nutritional evaluation of varying protein: energy ratios in feeds for Indian white shrimp Penaeus (Fenneropenaeus) indicus

Six experiments of six weeks duration were conducted in controlled conditions in the Indian white shrimp Fenneropenaeus indicus early juveniles (~0.040 mg initial weight). A common ingredient mixture (CIM) consisting of albumin (chicken egg), fish meal, shrimp meal, clam meal and deoiled ground nut oil cake was formulated and incorporated in all feeds at varying levels to obtain the requisite protein: energy combinations. Eight feeds tested in each experiment were formulated by incorporating CIM, cellulose (filler), tapioca flour (starch, binder), oil, mineral mixture, vitamin mixture and other additives viz., cholesterol and lecithin. The six protein levels fixed were 250 g kg-1 to 500 g kg-1 with 50 g kg-1 increments for each experiment. The gross energy (GE) levels in the eight dietary treatments for each level of protein varied from 290 kcal 100g-1 to 430 kcal 100g-1 and the digestible energy levels varied from198 – 300 kcal 100g-1. Growth, relative growth rate (RGR), absolute growth rate (AGR), food conversion efficiency (FCE), food conversion ratio (FCR), survival and initial and final body composition were monitored and analysed. One-way analysis of variance (ANOVA) followed by comparison of means was done to examine statistically significant differences between treatments and second degree polynomial regression of the from y = a + bx + cx2 was fitted with the data for RGR on P/E ratio (mg protein kcal-1), RGR on GE and RGR on DE to derive the optimum RGR, GE, DE and P/E. The results showed that growth of shrimp was highest with 450 g kg-1 protein and 363 kcal 100g- 1 GE, 276 kcal 100g-1 DE with a P/E of 124. Theoretical optima derived confirmed this observation with optimal values of 360 kcal 100g-1 GE, 275 kcal 100g-1 DE and a P/E ratio of 125. However, similar response in growth with feeds containing 350 - 450 g kg-1 protein indicating GE requirement of 362 – 371 kcal 100g-1 and DE requirement of 262 – 276 kcal100g-1 suggested a protein sufficiency of 350 g kg-1 with a P/E ratio of 98- 103 without major variations in the whole body composition.

Study of the chemical and nutritional characteristics of commercial dog foods used as elimination diet for the diagnosis of canine food allergy

ReferencesHypoallergenic” pet foods are commercial dietary products for dogs and cats used as elimination diets for the diagnosis of adverse food reactions. Aim of this study was to compare chemical and nutritional characteristics of this kind of dog foods with regular maintenance diets. Twenty-nine dry pet foods (pellets) were collected and divided into classes on the basis of the type (H: hypoallergenic; R: regular), source of fat (with or without fish oil) and source of protein (with or without fish protein) used in their composition. Labels of the H pet foods identified 8 products (44%) with one protein in their formula, suggesting that only few commercial manufacturers concern about the number of protein sources included in their products. Samples of the two groups showed different chemical profiles with lower levels of protein, gross energy, phosphorus and better fatty acid profile (expressed as % of total fatty acids) for H products in comparison to R foods: PUFA, 38.91 vs 24.03, P<0.01; ω3, 5.70 vs 2.58, P<0.01; ω6, 33.22 vs 21.63, P<0.01; DHA, 2.85 vs 0.16, P<0.05; CLA, 0.24 vs 0.08, P<0.05, for H and R respectively. This study suggests that the differences observed in the fatty acids composition may be attributed to fish proteins addition, but not to fish oil, in H pet foods production.

Milking strategy in subantarctic fur seals Arctocephalus tropicalis breeding on Amsterdam Island: evidence from changes in milk composition.

Milk composition was investigated throughout the 10-mo pup-rearing period in subantarctic fur seals (Arctocephalus tropicalis) breeding on Amsterdam Island. The mean milk composition was 42.8% +/- 5.7% lipid, 12.1% +/- 1.5% protein, and 42.6% +/- 7.3% water. Subantarctic fur seals breeding on Amsterdam Island produced one of the richest milks ever reported in otariids (20.4 +/- 2.9 kJ/g), with lipid content contributing 85% of total gross energy. The high lipid levels measured in the milk of subantarctic fur seals breeding on Amsterdam Island is consistent (i) with the relatively long time lactating females spend at sea, due to the relatively poor local trophic conditions near the colony that necessitate that they travel long distances to reach the foraging grounds, and (ii) with the consequently short time mothers spend with their pups ashore. Milk composition changed according to the time mothers were fasting ashore: milk produced during the first 2 d spent ashore, when more than 80% of milk transfer occurred, had higher levels of lipids, proteins, and gross energy than milk produced later during the visit ashore, suggesting that the pups were fed with two types of milk during a suckling period. Throughout the year, mothers in good condition produced milk of higher lipid content than others, suggesting that individual foraging skills contribute to enhance milk quality. Milk lipid and gross energy content varied with pup age, according to quadratic relationships, increasing during the earlier stages of lactation before reaching asymptotic values when pups were 180 d old. The stage of lactation appears to be a better predictor of milk lipid content than the duration of the preceding foraging trip, suggesting that either changes in the nutritional requirements of the pup and/or seasonal changes in trophic conditions act on milk composition. These changes in milk quality may also be related to changes in maternal care; lactating subantarctic fur seals apparently reallocate their body reserves toward gestation rather than lactation at the end of the pup-rearing period.

Avaliação de duas variedades de cana-de-açúcar submetidas a diferentes tempos de armazenamento

Foram estudadas duas variedades de cana-de-açúcar (CO 413 e RB 72 454), com o objetivo de verificar o efeito do armazenamento pós-corte sobre suas características tecnológicas e bromatológicas. As variedades foram cortadas e armazenadas durante zero, 1,5, 3,0 e 4,5 dias. Utilizou-se o delineamento inteiramente casualizado em esquema fatorial 2 x 4 . A variedade RB 72 454 apresentou melhor maturação que a variedade CO 413. O armazenamento proporcionou aumento no teor de açúcares redutores (P&lt;0,01) e diminuição no teor protéico (P&lt;0,01) das variedades de cana em estudo. A variedade RB 72 454 apresentou maior teor de matéria seca (P&lt;0,01). Ambas as variedades, quando armazenadas durante 4,5 dias, apresentaram queda de 14,66 e 4,04% nos teores de proteína bruta e energia bruta, respectivamente.

Effects of dietary lipid and carbohydrate levels on growth and body composition of juvenile red drum, Sciaenops ocellatus

Juvenile red drum (2.9 ± 0.3 g) were led one of six experimental diets (containing fish meal, crab meal, fish oil, wheat middlings, mineral and vitamin supplements, cellulose filler and binder) that provided 32% crude protein and 6 or 10% lipid, at three gross-energy (GE) levels ( 15.8 ± 0.3,17.1 ± 0.2 and 18.7± 0.3 kJ/g). Dietary carbohydrate (NFE) levels ranged from 24 to 39%. Significantly ( P < 0.05) higher weight gain (481%), feed efficiency (FE: 0.375), apparent net protein retention (ANPR: 19.77%) and apparent net energy retention (ANER: 10.81%) were associated with a diet containing 16.1 kJ GE/g, 10% lipid and 24% NFE. Survival (71–88%) did not differ significantly among dietary treatments. Weight gain, FE, ANPR and ANER of red drum was inversely related to dietary energy level and dietary carbohydrate content. Body lipid levels were significantly ( P < 0.05) higher in fish fed 10% lipid diets than in those fed 6% lipid. Dietary lipid exhibhted greater proteinsparing action than dietary carbohydrate, at all energy levels tested. The ability of juvenile red drum to utilize dietary carbohydrate as an energy source may be limited in comparison with warnwater omnivorous species like channel catfish and common carp.

The digestibility of foodstuffs and the effects of feeding selectivity on digestibility determinations in tilapia, Oreochromis niloticus (L)

The coefficients of digestibility for crude protein and gross energy of several foodstuffs used in Jamaican tilapia feeds were determined for the Nile tilapia, Oreochromis niloticus (L). Fingerling-sized males in aquaria received essentially single-ingredient diets containing approximately 80% of the test foodstuff, at a rate of 3% of wet body weight per day. The foodstuffs tested were: fish meal (sardine), poultry-offal meal, soybean meal, wheat middlings, brewers dried grains, raw ground corn, and an animal-based oil. Chromic oxide was used as a digestibility indicator. The feeding action of O. niloticus suggested that they practised preferential feeding on certain dietary components. Indeed, differences in the levels of crude protein and gross energy, and of the indicator, were found between samples of food taken from the diet, and from the stomach contents of fishes receiving these diets. No trend was apparent regarding differences in the levels of crude protein, but the levels of gross energy were consistently lower in the stomach samples (e.g., 4.6 vs. 4.9 kcal/g, soybean meal diet; 4.7 vs. 4.9 kcal/g, wheat middlings diet), while the concentrations of indicator were consistently higher in the stomach samples (e.g., 0.165 vs. 0.145 ABS, soybean meal diet; 0.109 vs. 0.085 ABS, brewers grain diet). These differences were found to result in variations of 0.2%–28.0% between estimations of the digestibility coefficients calculated from nutrient:indicator ratios in the diet and in the stomach contents. Consequently, in the present study these estimations were made using food taken from the stomach contents as being representative of the diet received by the fish. The digestibility coefficients for protein were: soybean meal (91%), fish meal (86%), ground corn (83%), wheat middlings (75%), poultry-offal meal (74%), and brewers grain (63%). In regard to gross energy, the digestibilities were: animal oil (93%), fish meal (80%), ground corn (76%), poultry-offal meal (59%), wheat middlings (58%), soybean meal (56%), and brewers grain (30%). It was apparent that the protein and energy of the animal-based foodstuffs were more available to O. niloticus than that of the plant-based foodstuffs.