Metabolizable Energy Coefficients Research Articles

Brazilian Corn Ethanol Coproducts for Pigs: Feeding Value and Blood Parameters.

This study aimed to determine the values of net energy (NE), digestible energy (DE) and metabolizable energy (ME) and digestibility coefficients of corn ethanol coproducts produced in Brazil and their effects on the nitrogen balance and blood parameters of pigs. Ten barrows were housed in metabolic study cages for total collection and fed a reference diet (RD) or 800 g/kg RD + 200 g/kg of a coproduct of corn ethanol. Distiller's dried grains with solubles (DDGS), corn bran with solubles (CBS), distiller's dried grains (DDG) and high-protein distiller's dried grain (HPDDG) were evaluated. The experimental design was randomized blocks with three repetitions per period, totaling six repetitions per diet. Diets containing the HPDDG had greater DE and ME than those containing CBS and DDGS and greater DE than those containing the DDG (p < 0.05). HPDDG, DDG, CBS and DDGS showed 4498, 3419, 3029 and 3335 kcal/kg DE; 4366, 3305, 2934 and 3214 kcal/kg ME; and 2515, 1938, 1649 and 1725 kcal/kg NE, respectively. Pigs fed diets containing HPDDG and CBS showed greater nitrogen retention efficiency than pigs fed DDGS (p < 0.05). Pigs fed diets containing HPDDG had higher blood urea levels than pigs fed CBS and RD, while triglyceride levels in animals that received the CBS diet were greater than those in animals that received all other diets. The HPDDG had the highest energy levels and the best digestibility coefficients. The chemical composition of coproducts influences the nitrogen balance and circulating levels of urea and triglycerides in pigs.

Using probiotics to improve nutrient digestibility and gut-health of weaned pigs: a comparison of maternal and nursery supplementation strategies.

Maternal probiotic supplementation has been found to have a positive impact on the gut health of piglets, not only during the lactation period, but also after weaning. Providing probiotics to nursery pigs is also a common strategy for supplementation. The goal of this study was to evaluate which would be the most effective strategy to improve nutrient digestibility, energy metabolism, and intestinal health in weaned pigs considering the maternal or nursery options. A total of 32 newly weaned pigs were randomly split into a 2 × 2 factorial arrangement considering maternal probiotic supplementation (with or without) in gestation-lactation and probiotic supplementation in the nursery period (with or without). After weaning, experimental diets were provided for 22 days. Total fecal and urine collection was performed from day 15 to 21. Blood samples were collected from all pigs on days 3 and 22 of the experiment to assess serum biochemistry and intestinal permeability. All pigs were euthanized on day 22 for intestinal tissue collection. Pigs born from probiotic-fed sows had greater (p < 0.05) total tract digestibility of dry matter (+1%) and gross energy (+1.3%), and greater (p < 0.05) metabolizable energy coefficient (+1.3%), which resulted in a 46 kcal/kg increase (p < 0.05) in the metabolizable energy content of the diet. Nitrogen intake (p = 0.035), uptake (p = 0.007), and retention (p = 0.012) were all increased in these pigs. Fecal moisture was reduced in pigs born from probiotic-fed sows and pigs fed the probiotic diet only in the nursery (p < 0.05). Pigs born from probiotic-fed sows had reduced intestinal permeability by 16% (p < 0.05), whereas pigs fed the probiotic diet in the nursery only tended to improve this response (p < 0.10). The villus:crypt ratio of pigs born from probiotic-fed sows was greater compared to the control (p < 0.05), while serum levels of alanine aminotransferase were lower (p < 0.05). Pigs born from probiotic-fed sows had increased nutrient digestibility and improved gut health. Therefore, it is concluded that supplementing the sow diets with probiotics rather than just providing diets in the nursery phase is an advantageous strategy.

Intake and digestibility of two diets for nine-banded armadillos (Dasypus novemcinctus: Linnaeus, 1758) kept under human care.

The study aimed to evaluate metabolic parameters, nutrient intake, and absorption of two diets formulated for Dasypus novemcinctus armadillos under human care. Were studied two diets: D1-a diet with dry dog food, ground beef, and boiled chicken egg with shells; D2-a diet with the same ingredients as D1, with added banana and papaya. Both are mixed in water. The parameters analyzed were body weight (BW), weight gain (WG), maintenance energy requirement (MER), Lee index, biometrics, body condition score, glucose, triglycerides, total cholesterol, and cholesterol fractions for eight male armadillos. Dietary intake (DI) and efficiency, nutrient intake, metabolizable energy, and digestibility coefficient for the diets were evaluated in six male armadillos. The diet that included fruits showed higher BW, WG, MER, Lee index, and better glucose metabolism. Both diets promoted increases in WG and Lee Index, as well as improvements in glucose metabolism. The diet without fruit improved the lipid profile of the animals. D2 presented the highest DI, better dietary efficiency, and higher energy intake but also a lower crude fiber intake. However, it showed the best utilization of gross fiber and all other nutrients. In conclusion, the diets constituted an adequate nutritional option for captive armadillos and can be used in malnutrition and pathological processes recovery. Although both diets were adequate, the nonfruit diet was preferable due to the improved lipid profile.

Determination and prediction of digestible energy, metabolizable energy, and standardized ileal digestibility of amino acids in barley for growing pig

Two experiments were performed to determine the digestible energy (DE), metabolizable energy (ME) and standardized ileal digestibility coefficients (SIDC) of amino acids (AA) in barley for pigs, and to develop prediction equations for the DE, ME and SIDC of AA based on its chemical composition. In Exp. 1, twenty-two castrated male pigs (29.5 ± 1.3 kg) were allotted to a replicated 11 × 3 incomplete Latin square design, including 11 diets and 3 consecutive periods. A corn-soybean meal basal diet and 10 test diets containing 400 g/kg of each barley at the expense of corn and soybean meal were prepared, and all diets had a constant ratio of corn to soybean meal. Each period includes 7 d of adaption and 5 d of total feces and urine collection. The DE and ME contents were measured by the total collection method. In Exp. 2, twenty-two ileal-cannulated pigs (30.5 ± 2.1 kg) were used in a duplicated 11 × 3 incomplete Latin square design with 11 diets and three 7-day periods. Titanium dioxide (3 g/kg) was added to all diets as indicator and ieal digesta were collected on d 6 and 7 of each period. Barley was the sole nitrogen source in 10 barley diets and a nitrogen-free diet was used for the endogenous nitrogen losses. The results showed great variations in ether extract (EE), calcium (Ca), ash, acid detergent fiber (ADF) and crude fiber (CF) among samples of barley. On an air-dry basis, the DE and ME in barley for pigs were 12.26 (11.29–13.58) MJ/kg and 11.87 (10.95–13.15) MJ/kg, respectively. The optimal prediction equations for DE and ME were: DE (MJ/kg) = −23.594 + 0.358 crude protein (CP) + 0.043 EE (R2 =0.95) and ME (MJ/kg) = 0.338 + DE - 0.014 ADF (R2 =0.99), respectively. The SIDC of lysine (Lys), methionine (Met), threonine (Thr), and tryptophan (Trp) in barley were 0.767 (0.731–0.809) g/kg, 0.825 (0.803–0.872) g/kg, 0.809 (0.793–0.822) g/kg, and 0.794 (0.760–0.858) g/kg, respectively. The best-fit prediction equations for SIDC of Lys, Met, Thr and Trp in barley fed to pigs were: SIDC Lys = 0.721 + 0.002 EE (R2 =0.79), SIDC Met = 1.045–0.00041 total starch (R2 =0.69), SIDC Thr = 0.739 + 0.001 ADF (R2 =0.69) and SIDC Trp = 1.468–0.006 CP - 0.001 neutral detergent fiber (R2 =0.99), respectively. The study confirms the large variations in chemical composition of different sources of barley, which contributes to the differences of DE, ME and SIDC of AA in barley fed to pigs and the fiber fraction can be used as key predictors.

Composition and availability of nutrients of three corn hybrids dried at different temperatures in the diets of broiler chickens

The objective of this study was to determine the chemical composition, non-starch polysaccharides (NSP) content, in vitro digestibility of starch, apparent metabolizable energy (AME), nitrogen-corrected AME (AMEn), and apparent and apparent nitrogen-corrected coefficient of metabolizable energy (ACME and ACMEn) of three corn hybrids dried at different temperatures in the diets of broiler chickens. The energetic values were determined by the total collection of excreta method, using broilers from 11 to 21 d, placed in a completely randomized design in [...]

Digestibilidade aparente e valor energético do ovo integral em pó para frangos de corte

Com a necessidade de buscar alimentos alternativos que visam baratear os custos na ração de frangos de corte e reaproveitar os resíduos de incubatório que compreendem material residual do processo de incubação, objetivou-se avaliar a digestibilidade e valor energético do ovo em pó desidratado para frangos de corte. Foram utilizados 300 frangos machos da linhagem COBB, distribuídos em delineamento experimental inteiramente casualizado, composto por dois tratamentos constituídos por cinco repetições, com três animais em cada repetição. O experimento foi composto por um tratamento controle (ração referência) e um tratamento composto por ração referência + 15% de ovo desidratado em pó. Foi utilizado o método de coleta total de excretas para realizar as análises. Nas avaliações foram constatadas 7,010Kcal/kg de energia metabolizável e coeficiente de digestibilidade da proteína bruta e da matéria seca de 86,81% e 72,17%, respectivamente. Conclui-se que o Ovo em pó integral desidratado pode ser utilizado adequadamente na alimentação de frangos de corte, pois possui alto valor energético e boa digestibilidade, assim seguindo os parâmetros nutricionais descritos.

Evaluation of the Interaction Between Phytase and Xilanase on Metabolizability of Energy-Reduced Broiler Diets

To examine the association between phytase and xylanase in diets with nutritional adjustments on the metabolizability of feed by broiler diets, 250 chickens were used and distributed among five treatments and five replicates of 10 broilers each. The treatments were: positive control diet - without phytase or xylanase; negative control diet - with an energy reduction of 0.419 MJ/kg, without phytase or xylanase; and three diets containing xylanase and phytase and energy reductions of 0.209, 0.409 and 0.628 MJ/kg. For all energy-reduced diets, the nutritional matrix of phytase with phosphorus (0.15%), calcium (0.165%) and sodium (0.035%) was considered. The energy reduction of 0.628 MJ/kg with inclusion of the enzymes resulted in a higher metabolizability of the crude protein, also the apparent and apparent corrected metabolizable energy coefficients for nitrogen balance were higher in diets with a reduction energy of 0.209 MJ/kg, however had values similar to those obtained in the positive control diets and diets with energy reduction of 0.628 MJ/kg containing enzymes. The inclusion of phytase (500 FTU/kg) and xylanase (16,000 BXU/kg) in broiler diets, makes it possible to reduce metabolizable energy by up to 0.628 MJ/kg, available phosphorus, calcium, and sodium, and improve the metabolizability of the nutrients.

Metabolizable Energy and Metabolizability Coefficients of Moringa and Bocaiuva for Slow-Growing Broilers at Different Ages

This study aimed to determine nutrient metabolizability coefficients and apparent metabolizable energy (AME) and nitrogen-corrected AME (AMEn) values of moringa leaf meal and bocaiuva pulp for slow-growing broilers. Three hundred and fifty 1-day-old chicks of the Red Naked Neck line were allocated to five treatments in a completely randomized design with seven replicates of 10 birds. Treatments consisted of a control diet and four test diets. The proportion of ingredients evaluated in the test diets was 20% moringa leaf meal and bocaiuva pulp and 40% corn and soybean meal. The total excreta collection method was applied with 1% ferric oxide included in the diets as a marker of start and end of collection, in the starter, grower and finisher phases. The metabolizability coefficients of dry matter, crude protein and ether extract and the AME and AMEn values of moringa leaf meal, bocaiuva pulp, corn and soybean meal were determined. Data were subjected to analysis of variance and means were compared by Tukey’s test at the 5% probability level. The protein from moringa leaf meal and the fat from bocaiuva pulp are highly metabolizable by birds at different ages. The AME and AMEn values of moringa leaf meal ranged from 2557 to 2868 Kcal/kg and 2205 to 2479 Kcal/kg, respectively. In bocaiuva pulp, AME and AMen ranged between 2680 and 3119 Kcal/kg and 2483 and 2490 Kcal/kg, respectively. Therefore, the alternative ingredients can be used in the formulation of diets for slow-growing broilers to partially replace corn and soybean meal.

Impact of an alternate feeding program on broiler breeder pullet behavior, performance, and plasma corticosterone

Broiler breeders are commonly feed restricted using some variation of skip-a-day feeding to prevent excessive body weight (BW) gain and poor flock uniformity that results in lower production levels. However, the level of feed restriction has increased leading to negative effects on broiler breeder welfare. Research needs to be conducted to evaluate alternative feeding programs to diminish the negative impact of restricted feeding on bird welfare. This research examined pullets that were fed soybean hulls (alternate day feeding, ATD) on the off day of a traditional skip-a-day feeding program in comparison to the standard skip-a-day program (SAD). The 2 dietary feeding treatments each had 3 replicate pens of 210 pullets each and were fed from wk 5 to 21 of age. Nitrogen-corrected true metabolizable energy and digestible amino acid coefficients of soybean hulls were determined. Body weight in the ATD feed program was significantly higher (P < 0.001) than the birds on the SAD feed program until 16 wk of age. Feed allocations for the SAD feeding program was increased at 11 wk of age to achieve similar BW prior to photo stimulation. The ATD feed program significantly improved BW uniformity of the birds for weeks 8, 12, 16, and 20. Hens fed on the SAD feed program had a lower mean egg production than the hens fed on the ATD program. There were significant differences on plasma corticosterone concentrations between the feeding days (24 or 48 h after feeding) in both feed programs. There was a shift in the behavior of the birds with significant differences in the feeding, foraging, and comfort behaviors between the feeding programs on the same feed day. Overall, feeding the ATD females soybean hulls on the off feed day improved the BW uniformity and egg production, but further research will be needed to determine potential differences in nutrient utilization or behavior of the pullets that positively impacted this flock performance.

Immune modulation, growth performance, and nutrient retention in broiler chickens fed a blend of phytogenic feed additives.

This study aimed to assess the effect of a commercial blend of phytogenic feed additives (PA), comprising 5% carvacrol, 3% cinnamaldehyde, and 2% capsicum oleoresin on the modulation of immune biomarkers of broiler chickens, their growth performance, dietary energy, and nutrient retention. Four-hundred day-old birds were assigned to one of four dietary treatments. Two control diets based on either wheat (WC) or maize (MC) were each given with and without PA at 100g/t. Growth performance variables including feed intake (FI), weight gain (WG), and feed conversion ratio (FCR) were recorded. Dietary N-corrected apparent metabolizable energy (MEn), dry matter (DMR), nitrogen (NR), and fat retention (FR) coefficients were also determined. Gene expression of immune biomarkers (cytokines) were determined in caecal tonsil tissue from 21 d old birds. Expression of IL2, IL18, IL10, and IL17C in the caecal tonsils were upregulated (P < 0.05) in the birds fed MC-based diets compared to the WC fed birds. Feeding PA supplemented diets downregulated the expression of CD40LG (P < 0.001), IFNG, and IL6 (P < 0.05). There was a cereal type × PA interaction (P < 0.05), as expression of IFNB was downregulated in the birds fed PA supplemented MC but not WC. However, expression of IL12B was downregulated in birds fed PA supplemented WC but there was no significant (P > 0.05) change in expression levels in birds fed MC diets. Feeding MC diets gave greater FI (P < 0.001) and ME (P < 0.05), but lower FCR (P < 0.05) compared to birds fed WC diets. The WG and nutrient retention coefficients were not affected (P > 0.05) by cereal type. Supplementary PA improved FI (P < 0.05), WG (P < 0.001), FCR (P < 0.05), MEn (P < 0.05), MEn: GE ratio (P < 0.05), and FR (P < 0.05). In conclusion, dietary inclusion of PA improved overall growth performance variables, energy, and nutrient retention and intestinal cytokine expression.

Nutritional value of distillers dried grains with solubles from corn and sorghum and xylanase in diets for pigs

ABSTRACT Two experiments were conducted to evaluate the digestibility and energy of distillers dried grains with solubles (DDGS) from corn and sorghum with or without xylanase enzyme in diets for pigs. The values of dry matter (DM), organic matter (OM), crude protein (CP), mineral matter (MM), ether extract (EE), neutral detergent fiber (NDF), gross (GE), digestible (DE), metabolizable energy (ME), and digestibility coefficients (DC) were determined. In the experiment 1, we used eight barrows of 26.15±3.45 kg with repeated measures [...]

&lt;b&gt;Digestibility and physico-chemical characteristics of acid silage meal made of pirarucu waste in diets for commercial laying hens

The objective of this study was to evaluate the effects of acid silage meal made of pirarucu waste in diets for commercial laying hens on apparent digestibility and energy metabolism. Seventy-two Hisex White hens with 71 weeks of age were assigned to a completely randomized with two treatments (control diet and diet with 3% pirarucu waste acid silage) with six replicates of six birds each. The ensiled biomass was light brown in color, showing acidified aroma; creamy consistency; 4.38±0.11 pH; 84.16% dry matter; 40.06% crude protein; 26.82% ether extract; 9.31% mineral matter, 65.16 g kg-1 calcium and 22.90 g kg-1 phosphorus. Differences (p &gt; 0.05) were detected in digestibility of crude protein, non-fiber carbohydrates (soluble carbohydrates), etherextract, mineral matter, metabolizable energy and metabolizable energy coefficient. Our results indicate that the acid silage mealmade of pirarucu waste can be included up to 3% in diets for laying hens, showing satisfactory nutrient digestibility and potential to be used as an energy source.

Use of okara (aqueous extract residue) in the diet of starter broilers

Two experiments were carried out to determine the chemical composition of okara and to evaluate the performance and carcass yield of broilers fed diets containing increasing levels of okara. In experiment 1, a total of 72 21-d-old Cobb male broilers were distributed in an entirely randomized experimental design consisting of three treatments and four replicates of six birds each. The energy in okara was 2972 kcal of AME kg−1, with an apparent metabolizable energy (AME) coefficient of 60.72 (% dry matter). In experiment 2, a total of 840 male Cobb male chicks were distributed in an entirely randomized experimental design consisting of six treatments (0.0%, 2.5%, 5.0%, 7.5%, and 10% okara inclusion) and six replicates of 28 birds each. The inclusion of increasing levels of okara from 1 to 21 d of age linearly reduced (P &lt; 0.05) weight gain and feed intake, without affecting (P &gt; 0.05) feed conversion, carcass, breast, drumstick, and thigh yields at 42 d of age. Economic analysis indicated that a 10.0% inclusion level of okara in broiler diets during the starter phase produced the best economic results.

Casca de soja na alimentação de codornas

Soybean hulls are a byproduct resulting from the soybean processing industry; however it has high fiber content, there are some evidences that quails can digest more fibrous ingredients compared to hens. Thus, this study aimed to evaluate the digestibility and the effects of different levels of soybean hulls on performance, egg quality, gastrointestinal organs weight and serum cholesterol and triglycerides levels of quails. For this, two experiments were conducted. On the first experiment, a digestibility assay was conducted, using 120 male quails at 30 days of age randomly assigned in two treatments: reference diet and test diet (partial replacement of reference with 20% of soybean hulls) with 10 replications and six birds per experimental unit. On the second experiment, two hundred eighty female quails at 150 days of age were randomly assigned in five levels of soybean hulls inclusion: 0; 5; 10; 15 e 20%, seven replications and eight birds per experimental unit. The apparent metabolizable energy (AME) and nitrogen-corrected apparent metabolizable energy (AMEn) and respective metabolizability coefficients were determined to be 1,844.47 and 1,783.81 kcal/kg of dry matter basis, 49.53 and 46.64%, respectively. The soybean hulls inclusion did not affect the performance, egg quality, serum cholesterol and triglycerides. Among the gastrointestinal organs, the inclusion of soybean hulls affected only the pancreas. These results suggest that quail can be included in the quail diets until the level of 20%.

The TMEn, Proximate Analysis, Amino Acid Content and Amino Acid Digestibility of Glandless and Commercial Cottonseed Meal for Broilers

Cotton seed meal (CSM) is an alternative ingredient in poultry diets but its use is limited due to the presence of gossypol and the potential effects of gossypol on digestibility of nutrients. Glandless cottonseed is available and contains very low gossypol but there has been a limited amount of poultry nutritional studies completed with glandless cottonseed meal (GCSM). The TMEn, proximate analysis, amino acid content and amino acid (AA) digestibility of a glandless (GCSM) and a commercial (CCSM) cottonseed meal were determined with broilers. Thirty 42-day old Cobb 500 male broilers were precision-fed 30g of CCSM, GCSM and glucose and excreta collected during a 48 h period. Glucose was fed to serve as a control (no nitrogen or AA content). The chemical composition, gossypol content, True metabolizable energy (TMEn) and digestibility coefficients for AA were calculated for both meals. The crude protein and fat content of GCSM was higher than the CCSM (54 and 51%, 6 and 2%, respectively). Both meals were similar in calcium, total phosphorus and phytic acid contents. The CCSM had a higher content of total and free gossypol (1.52 and 0.161%, respectively) when compared to GCSM (0.02 and .003%, respectively). The TMEn for the GCSM provided approximately one thousand kcal more per energy/ kg than the CCSM. The essential AA content (g/kg; 90% DM) was determined for both cottonseed meals and was generally higher for GCSM compared to CCSM but both types of CSM contained higher levels of key essential AA than reported values for AA in the literature. The most extreme differences were for methionine and cystine; % methionine content was approximately 2 fold higher than values in the literature and the % cystine was 74 to 93% higher. The true digestibility coefficients for essential AA ranged from the low of 73.9% for isoleucine to 91.8% for arginine, for CCSM; the amino acid digestibility coefficients for GCSM were all higher than 90% for the essential AAs.

Desenvolvimento de materiais adsorventes de óleos a partir de resíduos do beneficiamento do café e sua aplicação na ração para aves

O objetivo deste trabalho foi modificar quimicamente resíduos do beneficiamento do café (pergaminho), visando a obtenção de um produto mais hidrofóbico, testá-lo quanto ao seu poder adsorvente de óleo e utilizá-lo em formulações de rações para aves. Os resíduos foram analisados quanto a sua composição química-bromatológica e, posteriormente, acetilados com anidrido acético usando diferentes concentrações de N-bromossuccinimida, a temperatura de 120°C por 4 horas. A análise dos resíduos indicou altos teores de fibras. A acetilação possibilitou ganho de massa em todas as amostras estudadas. Nos testes de adsorção de óleo verificou-se aumento significativo na retenção de óleo dos materiais modificados, comprovando a hidrofobização. O material acetilado e com certa quantidade de óleo adsorvida foi chamado de OSoL (óleo sólido) sendo avaliado o seu valor nutricional em rações para aves, substituindo o óleo de soja. Nos ensaios metabólicos adotou-se o método de alimentação forcada, sendo determinados os valores de energia metabolizável verdadeira, energia metabolizável verdadeira corrigida para nitrogênio, coeficiente de digestibilidade da matéria seca, coeficiente de digestibilidade da proteína bruta e coeficiente de metabolizibilidade da energia metabolizável. Os tratamentos mostraram-se semelhantes estatisticamente, sendo, portanto, viável a inclusão do OSoL nas rações animais.

The effects of reproductive state on digestive efficiency in three sympatric bat species of the same guild

The functional link between food as an energy source and metabolizable energy is the digestive tract. The digestive organs may change in size, structure, or retention time in response to energetic demands of the animal. Very efficient digestive tracts may be better at processing food but require higher energetic investments for maintenance even when post-absorptive. These costs influence the resting metabolic rate (RMR) that is defined as the energy necessary to fuel vital metabolic functions in a resting animal. In bats a trade-off between the necessity for a highly efficient digestive tract and moderate energetic maintenance costs may be particularly important. We hypothesized that low RMR coincides with low digestive efficiency (defined as apparent metabolizable energy coefficient (MEC)) and that phases of increased energetic demand are compensated for by increased digestive efficiency. We measured RMR and apparent MEC in the bats species Myotis nattereri, M. bechsteinii, and Plecotus auritus. In support of our hypothesis, M. nattereri has the lowest mass-specific RMR of the three species and the lowest apparent MEC. However, apparent MEC did not change during phases with differing energetic demands in any of the bat species, probably because bats operate at the limit of their sustainable energy demand.

Diet, Food Preferences, and Digestive Efficiency of the Grayish Saltator, a Partly Folivorous Passerine

AbstractWe studied the diet of the Grayish Saltator (Saltator coerulescens) during the rainy and dry seasons in the Venezuelan llanos and examined its food preferences, digesta retention time, rate of food intake, and digestive efficiency, in captivity. Grayish Saltators fed almost exclusively on plant tissues throughout the year. Fruits and leaves were the most commonly consumed items, comprising 36% and 28% of the diet, respectively, averaged over the entire year. In pairwise choice trials, saltators preferred fruits over leaves and flowers, and wild over cultivated leaves. In the laboratory, saltators displayed food-processing traits typical of frugivorous passerines. When feeding on a fruit (banana mash) diet, they had a fast rate of food passage (digesta mean retention time = 54 ± 26 min) and a relatively low digestive efficiency (average metabolizable energy coefficient = 0.59 ± 0.11), which was compensated for by high rates of food intake (1.4 times body mass). Mean retention time of a leaf-supplemented diet was slightly shorter (average = 45 ± 17 min). Birds maintained or increased their body masses under laboratory conditions when fed on a fruit diet but did not when fed exclusively with leaves. Saltators spent very little time foraging, and the amount of time varied seasonally (5% and 17% of the time in the rainy and dry seasons, respectively). Most of their time (ca. 50%) was dedicated to resting. The morphology of the digestive tract of this species is similar to other frugivorous birds, but the inner edge of the maxilla is serrated. We found no evidence of cellulolytic activity in the Grayish Saltator's gut. Together, all of these characteristics indicate that Grayish Saltators are partial folivores that rely on a “skimming” strategy of food consumption.

Growth and Energy Requirements of Captive-Reared Common Loon (Gavia Immer) Chicks

AbstractWe measured the energy requirements during postnatal development of six hand-reared Common Loon (Gavia immer) chicks using continuous feeding trials and doubly labeled water. At fledging, the mean (± SE) body mass of chicks was 3,246 ± 51 g. They reached asymptotic body mass in ≈66 days and had a mean growth rate constant of 0.089 ± 0.002 day−1, which was greater than growth rate constants of other, similar-sized precocial birds. Between hatch and day 66, chicks allocated 16.5% of their metabolizable energy to new tissue, lower than the average for other bird species (20%), which might be expected considering their precocial mode of development. There was a developmental change in the assimilation efficiency of food (metabolizable energy coefficient), with a mean of 0.64 ± 0.03 in chicks aged 21 days, rising to 0.83 ± 0.07 in chicks aged 35 days.Les besoins en énergie durant la croissance chez des jeunes Gavia immer élevés en captivité

GROWTH AND ENERGY REQUIREMENTS OF CAPTIVE-REARED COMMON LOON (GAVIA IMMER) CHICKS

Abstract We measured the energy requirements during postnatal development of six hand-reared Common Loon (Gavia immer) chicks using continuous feeding trials and doubly labeled water. At fledging, the mean (± SE) body mass of chicks was 3,246 ± 51 g. They reached asymptotic body mass in ≈66 days and had a mean growth rate constant of 0.089 ± 0.002 day−1, which was greater than growth rate constants of other, similar-sized precocial birds. Between hatch and day 66, chicks allocated 16.5% of their metabolizable energy to new tissue, lower than the average for other bird species (20%), which might be expected considering their precocial mode of development. There was a developmental change in the assimilation efficiency of food (metabolizable energy coefficient), with a mean of 0.64 ± 0.03 in chicks aged 21 days, rising to 0.83 ± 0.07 in chicks aged 35 days. Les besoins en energie durant la croissance chez des jeunes Gavia immer eleves en captivite