RESUMEN El objetivo fue determinar la energía metabolizable aparente (EMAn) y digestibilidad íleal aparente (CDI) de aminoácidos en la harina de calamar gigante (Dosidicus gigas) (HCG), como alternativa proteica en dietas para pollos de engorda. Experimento 1: en la HCG se determinó la EMAn y el CDI de sus aminoácidos. A 96 pollos se les proporcionó dieta con 8 y 16% de HCG durante 21 días de edad. Experimento 2: 72 pollos fueron alimentados con 16 y 20% de HCG en la dieta, durante 42 días. Variables productivas, rendimiento de canal, color de piel y sabor fueron evaluados. Resultados: EMAn fue 3376.15 kcal/kg y CDI de los aminoácidos mayor a 68%, excepto histidina (21%) y cisteína (47%). Ganancia de peso y peso final se redujeron con 16% HCG (P < 0.05) respecto al testigo a los 21 días de edad, sin embargo, a los 42 días no se detectaron diferencias (P > 0.05) entre tratamientos con 16 y 20%, tanto en las variables productivas como en rendimiento de la canal y peso de pollos (P > 0.05). El sabor de la carne no se vio afectado por HCG (P > 0.05). Se concluye que la HCG es una fuente alterna de proteína en dietas para pollos de engorda.

ABSTRACT The objective was to determine apparent metabolizable energy (AMEn) and apparent ileal digestibility (AID) of amino acids in giant squid (Dosidicus gigas) (GSM) meal, as a protein alternative in diets for broilers. Experiment 1: in GSM the AMEn and the AID of its amino acids were determined. Ninety-six chickens were fed a diet with 8 and 16% GSM for 21 days of age. Experiment 2: 72 chickens were fed with 16 and 20% GSM in the diet for 42 days. Productive parameters, carcass yield, skin color and flavor meat were evaluated. Results: AMEn was 3376.15 kcal/kg and AID of amino acids greater than 68%, except histidine (21%) and cysteine (47%). Weight gain and final weight were reduced with 16% GSM (P < 0.05) compared to the control at 21 days of age, however at 42 days no differences were detected (P > 0.05) between treatments with 16 and 20%, both in the productive parameters and in carcass yield and chicken weight (P > 0.05). The taste of the meat was not affected by GSM (P > 0.05). It is concluded that GSM is an alternate source of protein in diets for broilers.

ABSTRACT Laying hen welfare has been studied increasingly, some works concluded that the cage housing system provides poor welfare for laying hens. These have a great interest in Mexico because it is the world's leading egg consumer (22.8 kg per capita by year) and the fourth leading producer. The aim of this work was to evaluate laying hen welfare. Fifty 22-weeks-old Bovans White laying hens were housed in the floor, assigning 1200 cm2 per hen. Behavior, health, production parameters, and egg physical quality were evaluated at 22, 30 and 62 weeks. There was a difference (P<0.05) throughout the study in frequency and time of the following behaviors: dust bath, lie down, exploring and foraging. On the other hand, egg physical quality was according to the national regulations. At the end of the study, hens had good physical health and a wide behavior repertory.

RESUMEN El interés por el bienestar de las gallinas ponedoras ha ido en aumento y algunos estudios consideran que el sistema de alojamiento en jaulas proporciona un bienestar deficiente en las gallinas. Este tipo de estudios son de gran interés en México debido a que es el principal consumidor mundial de huevos (22.8 Kg per cápita anual) y cuarto productor a nivel internacional. Por lo tanto, el objetivo de la investigación fue realizar un estudio sobre el bienestar de gallinas ponedoras en piso. Para este propósito, 50 gallinas Bovans White fueron alojadas en piso, con espacio de 1,200 cm2 por ave. Fueron evaluadas a las 22, 30 y 62 semanas de edad su comportamiento, estado de salud, las variables de producción y la calidad física del huevo. Durante el estudio se observaron de manera general diferencias (P<0.05) en tiempo y frecuencia de las siguientes conductas: baño de tierra, echarse, explorar y forrajear. Por otra parte, la calidad física del huevo cumplió las normativas al respecto. Al final del estudio las gallinas mostraron un buen estado de salud y un amplio repertorio de conductas.

ABSTRACT Amaranth (Amaranthus cruentus L.) is a food high in protein and lysine content, and has a well-balanced amino acid composition. In addition, it has shown to be efficient in lowering egg cholesterol. The objective of this study was to evaluate the effect of different inclusion levels of Amaranthus cruentus L. in the diet of laying hens, on egg cholesterol content and production parameters. 200 laying hens of 30 weeks of age were fed on diets that included 0, 15, 30 and 45% (dry matter basis) of A. cruentus. For 2 months, weekly feed intake per hen, egg production per week, egg mass and feed conversion ratio were evaluated. 480 eggs were analyzed to determine cholesterol content by high performance liquid chromatography. The results were analyzed by analysis of variance for a randomized block design. The inclusion of 15% of A. cruentus seeds in the diet decreased egg yolk cholesterol content without significantly affecting the main production parameters.

RESUMEN El amaranto (Amaranthus cruentus L.) es un alimento de alto aporte en proteína, lisina y buen balance de aminoácidos. Además, ha demostrado ser eficiente para disminuir el colesterol del huevo. El objetivo de este estudio fue evaluar el efecto de diferentes niveles de inclusión de A. cruentus L. en la dieta de aves de postura, sobre el contenido de colesterol en el huevo y parámetros productivos. Se realizó un experimento con 200 gallinas Hy Line de postura de 30 semanas de vida, para evaluar la inclusión de A. cruentus en proporciones de 0, 15, 30 y 45% base materia seca. Durante 2 meses se evaluó el consumo semanal de alimento por ave, producción de huevos por semana, masa de huevo y conversión de alimento; 480 huevos fueron analizados para determinar el contenido de colesterol mediante cromatografía liquida de alto rendimiento. Los resultados fueron analizados mediante análisis de varianza en diseño de bloques al azar. La inclusión de semillas de A. cruentus en 15% de la ración disminuyó el colesterol en la yema de huevos, sin afectar significativamente los principales parámetros productivos.

Abstract: Crude soybean oil (CSO) is used to increase metabolizable energy (ME) content in diets for laying hens. Also used in human food, its price is consequently high. Oil soapstocks are byproducts of the oil extraction process and therefore cost less. An evaluation was done of the effect of two soybean soapstocks (SS) on egg production, quality and lipid composition, and the cost of 1 kilogram of eggs. Soapstock ME and lipid composition were quantified. An experiment was done using 240 hens in six treatments, with five replicates and eight hens per replicate. Diets were formulated using CSO, or one of the soapstocks, at 2 or 4% concentrations. The evaluated productive variables were feed intake, feed conversion, egg weight, egg mass, laying percentage and egg quality parameters. Egg lipid composition was described and the cost per one kilogram calculated. Replacement of CSO with the soapstocks did not affect poultry production variables (P>0.05), but did improve Haugh unit values (P<0.05). Egg fatty acids composition changed in response to oil composition (P<0.05), and inclusion concentration affected the levels of specific fatty acids. Use of the soapstocks resulted in a lower cost per kilogram of eggs than with CSO (P<0.05). Substitution of crude soy oil with the evaluated soapstocks had no effect on productive variables, improved egg quality and lowered overall feed costs.

Resumen: En la alimentación de gallinas en postura se utiliza el aceite crudo de soya (ACS), pero debido a que éste compite con la alimentación humana su precio es alto, por lo cual se evaluaron dos aceites acidulados de soya (AAS), los cuales son más económicos. El objetivo del estudio fue evaluar el efecto de los AAS en la producción de gallinas Bovans, calidad de huevo, composición lipídica y costo de un kilo de huevo. Se determinó la energía metabolizable (EM) y composición de lípidos de los acidulados. Se utilizaron 240 gallinas en seis tratamientos, con cinco repeticiones, con ocho gallinas cada una. En las dietas se incluyeron ACS y dos acidulados (AAST y AASY), a dos niveles (2% y 4%). Las variables productivas fueron alimento consumido, porcentaje de postura, peso del huevo, masa del huevo, conversión alimenticia; en calidad de huevo se midió altura de albumina, unidades Haugh (UH), color de yema y grosor de cascarón. Se determinó la composición lipídica del huevo y su costo. Al sustituir el ACS por los AAS no se afectó la producción de las aves (P>0.05). En calidad de huevo, los AAS mejoraron las UH (P<0.05); la concentración de ácidos grasos del huevo se modificó según la composición del aceite en la dieta de las gallinas (P<0.05), mientras que el nivel de aceite influyó en el contenido de algunos ácidos grasos. Finalmente los AAS disminuyeron el costo de un kilo de huevo (P<0.05) en comparación del ACS.

ABSTRACT The objective was to determine the effect of black tuna meal (BTM) at different concentrations and time of addition, in chicken diets on production variables, quality, and concentration of fatty acids in eggs and sensory evaluation. A 3 x 4 factorial design was used. Increasing the concentration of BTM modified the production variables. The cholesterol level was higher with 3% of BTM, the total lipids were increased at the time, the highest level was the control and the lowest with 3%, the Decosahexaenoic acid (DHA) was greater than 3% of BTM, the alpha-linolenic acid (ALA) did not obtain differences, arachidonic acid (AA) and linoleic acid (LA) showed their lowest values with 2% of BTM. As for the sensory evaluation, color, smell, and taste were well accepted. Therefore, it is concluded that BTM can be used to enrich the nutritional values of the bird´s diet.

RESUMEN El objetivo fue determinar el efecto de la harina negra de atún (HNA) a diferentes concentraciones y tiempo de adición en dietas para gallina sobre variables de producción, calidad y concentración de ácidos grasos en el huevo y evaluación sensorial. Se utilizó un diseño factorial 3 x 4. Se modificaron las variables de producción al aumentar la concentración de HNA. El nivel de colesterol fue mayor con 3 % de HNA, los lípidos totales se aumentaron al tiempo, el nivel más alto fue el testigo y el más bajo con 3 %, el ácido docosahexaenoico (DHA) fue mayor al 3 % de HNA, el ácido alfa linolénico (ALA) no obtuvo diferencias, el ácido araquidónico (AA) y el ácido linoleico (LA) mostraron sus valores más bajos con un 2 % de HNA. En cuanto a la evaluación sensorial color, olor y sabor tuvieron buena aceptación. Por lo que se concluye que la HNA puede ser utilizada para enriquecer los valores nutricionales de la dieta de las aves.

ABSTRACT: The objective of this study was to determine the effect of storage conditions on the water soluble fraction in eggs from hens fed with a conventional diet and a 20 % shrimp by-products meal (SBPM). Ninety (90) Isa-Brown laying hens 32 wk age were distributed in two treatments: Control and SBPM. The productive variables were evaluated during 4 wk. Eggs (n= 250) collected for this study, were stored at 15 and 30 d/ 20° and 4 °C, taking as reference fresh eggs (not stored). The parameters studied were egg weight, Haugh Units, pH, crude protein, essential amino acids and water soluble vitamins. The results were analyzed using a 2x2x3 factorial design and the differences between means were compared using the Tukey test. The data obtained showed that the quality indexes of the water soluble fraction of egg were significantly affected (P<0.05) by the time and the temperature of storage and differences (P<0.05) in protein alone due to the effect of SBPM inclusion. At room temperature (20 °C) and longer storage time (30 d), a decrease in internal egg quality was observed according to the results of this study. Therefore, it is concluded that both temperature and time are one of the main factors influencing the eggs quality of the water-soluble fraction of the egg during storage.

RESUMEN: El objetivo de este estudio fue determinar el efecto de las condiciones de almacenamiento, sobre la fracción hidrosoluble del huevo de gallinas alimentadas con una dieta convencional y una dieta con 20 % de harina de cabezas de camarón (HCC). Noventa (90) gallinas Isa-Brown de 32 semanas de edad se distribuyeron en dos tratamientos: Testigo y HCC. Durante cuatro semanas de ensayo se evaluaron las variables productivas. Los huevos recolectados (n= 250) para este estudio, se almacenaron por 15 y 30 días, a 20° y 4 °C, tomando como referencia huevos recién puestos (sin almacenar). Los parámetros estudiados fueron peso de huevo, Unidades Haugh, pH, proteína, aminoácidos indispensables y vitaminas hidrosolubles. Los resultados se analizaron utilizando un diseño factorial 2x2x3 y las diferencias entre medias se compararon mediante la prueba de Tukey. Los resultados obtenidos mostraron que los índices de calidad de la fracción hidrosoluble de huevo se vieron afectadas significativamente (P<0.05) por el tiempo y la temperatura de almacenamiento, y diferencias (P<0.05) solo en proteína por el efecto de la inclusión de HCC. A temperatura ambiente (20 °C) y mayor tiempo de almacenamiento (30 días), provocó una disminución en la calidad interna del huevo de acuerdo a los resultados de este estudio. Por lo tanto, se concluye que tanto la temperatura como el tiempo son uno de los principales factores que llegan a influir en la calidad de la fracción hidrosoluble del huevo durante el almacenamiento.

Abstract The aim of this study was to evaluate the effects of adding conjugated linoleic acid (CLA) to boar diets on semen production and characteristics, the fatty acid profile of spermatozoa, and on testicle and boar carcass parameters. Ten lean-type terminal-line (Yorkshire × Landrace × Pietrain) adult boars were randomly assigned to one of two treatments: (1) a control diet and (2) the same diet with 1 % CLA. The research was conducted in Mexico, and animals were exposed to ambient temperatures between 13.5 and 26.3 °C. Boars were ejaculated twice per week during a 12-week period to examine semen production and characteristics. The results suggest that supplementation of boar diets with CLA did not affect the spermatozoa fatty acid profile, semen volume, sperm concentration, viability, or motility, nor did it cause abnormal sperm morphology. Compared to controls, boars fed a CLA diet had a higher seminal pH and increased backfat thickness. In summary, this study indicates that CLA addition in boar diet does not change the semen characteristics or fatty acid profile of spermatozoa; however, it increases backfat thickness in sexually mature boars.

Introduction: the regular consumption of fish brings benefits to health due to its content of n-3 fatty acids, but cooking enhances or damages the concentration of fatty acids (FA) since they are susceptible to oxidation by temperatures and cooking times. Objectives: to analyze the effect of six cooking techniques on total lipids (TL) and (FA) content in marlin and hake and select which one helps the best conservation of health beneficial FA. Methods: fillets were subjected to different cooking techniques: steam (ST), foiled-aluminum-paper (FAP), foiled- banana-leaf (FBL), gas-oven (GO), microwave-oven (MO) and fried-lightly (FL). FA were identified by gas chromatography/FID. Results and discussion: Marlin: FL increased the concentration of TL and MO decreased it. Statistically, PUFA, SFA and EPA + DHA increased with FAP, MUFA decreased with FBL and increased in FL. Hake: FL increased concentration in all groups of FA while ST decreased it. SFA values and index of atherogenicity (IA), thrombogenicity (IT), peroxidisability and hipocolesterolemic/ hipercolesterolemic fatty acid ratio (HH) found, suggested that hake is a fish with greater health benefits, regardless of the technique you employ. By its EPA + DHA content, marlin seems to be an excellent choice if cooked FAP. FL technique in both species decreased the IA, IT and significantly increased the HH; however n3/n6 ratio decreased. ST seems to be the least desirable cooking technique for both species.

Introducción: el consumo frecuente de pescado aporta beneficios a la salud por su contenido en ácidos grasos n-3. Generalmente se consume cocinado pero la cocción mejora o perjudica la concentración de ácidos grasos(AG), pues son susceptibles a oxidarse por las temperaturas y tiempos de cocción. Objetivos: analizar el efecto de seis técnicas de cocción sobre los lípidos totales (LT) y AG de marlín y merluza y seleccionar la que favorece una mejor conservación de AG de importancia para la salud. Métodos: se sometieron los filetes a diferentes técnicas de cocción: vapor (VA), empapelado papel-aluminio (EA), empapelado hoja-plátano (EP), horno-gas (HG), horno-microondas (HM) y sofrito (SF). Los AG se identificaron por cromatografía de gases/FID. Resultados y discusión: Marlín: el SF aumentó la concentración de LT y el HM la disminuyó. Estadísticamente, los AGS, AGP y EPA + DHA aumentaron con EA, los AGM disminuyeron con EP y aumentaron en el SF. Merluza: el SF aumentó la concentración en todos los grupos de AG, mientras que el VA la disminuyó. Por los valores de AGS, índices de aterogenicidad (IA), trombogenicidad (IT), susceptibilidad a la peroxidación y relación hipocolesterolémica/ hipercolesterolémica de los ácidos grasos (HH) encontrados, se sugiere que la merluza es un pescado con mayores beneficios para la salud, independientemente de la técnica que se aplique. Por su contenido en EPA + DHA el marlín parece ser una excelente opción si se cocina en papel aluminio. La técnica de sofrito en ambas especies disminuyó el IA, IT y aumentó significativamente la HH, sin embargo la relación n3/n6 disminuyó. La técnica menos conveniente para ambas especies resultó ser el VA.

To analyze the effect of conjugated linoleic acid (CLA) on the meat of pigs (0,1%) and three crude protein (CP) levels (nursery: 20.5, 16.0, 14.5%; growing: 16, 14.5, 11.5%; and finishing: 14.0, 12.5, 11% CP), studies were conducted with 36 hybrid (Yorkshire×Landrace×Duroc) barrows (17.3-83.5 kg), which were individually penned and allotted in a completely randomized design in a factorial (2×3) arrangement for 84 d. The analysis by phases indicated that CP level affected some variables. Average daily gain, average daily feed intake, fat free lean gain, backfat thickness, longissimus muscle area and final body weight were reduced (P≤0.05) feeding the lowest CP diet in nursery and growing pigs. Plasma urea nitrogen concentration was also lower (P≤0.05) in the growing and finishing phases when fed the lowest CP level. The global analysis showed that all the analyzed variables (except feed gain ratio, lean meat percentage and plasma urea nitrogen concentration) were reduced (P≤0.05) in the pigs fed low-protein diets; plasma urea nitrogen concentration tended to be lower (P=0.07) when CP was reduced. The fatty acid profile of the meat (semimembranosus and longissimus muscles) indicated that CLA addition increased CLA isomers and total saturated fatty acids, and reduced the total monounsaturated fatty acids (P≤0.05). α-Linolenic acid was lowered in longissimus muscle of pigs fed LPD (P=0.08). These results indicated that reducing the crude protein concentration in the diet of fattening pigs from 20.5 to 16.0% in nursery phase; from 16.0 to 14.5% in growing stage; and from 14.0 to 12.5% in finishing pigs, did not negatively affect the growth performance, nor carcass characteristics. The results also showed that the addition of CLA did not improve pig response and the concentration of unsaturated fatty acids and total lipids altered the feeding LPD.

In order to determine the effects of shrimp (Penaeus spp.) by-product meal (SBM) on performance parameters, physical quality and sensory evaluation of fresh and stored eggs, 120 white Leghorn hens, 42 weeks old, were distributed in 4 replicates of five treatments (0, 10, 15, 20 and 25% SBM). At 28 days of the assay, eggs were collected from each treatment to evaluate physical quality at 0, 15 and 30 days of storage at 4 and 20ºC. A factorial design of 5×3×2 was used. There were no statistical differences in performance parameters (P>0.05). Average egg weight was higher (64.08g) with 15% SBM, without any detectable effect due to storage time. Haugh Units (HU) decreased in eggs stored at 20ºC (15 and 30 days), but not at 4ºC. Yolk color was reduced in treatments with SBM as compared with the control and was also altered by storage time at 20ºC. Eggshell weight was not affected by storage conditions or by the treatments. No differences (P>0.05) in eggshell thickness and sensorial evaluation (yolk color and taste) were found. It is concluded that the differences found were caused by storage time and temperature, not by the inclusion of SBM in laying hens’ rations.

Para conhecer o efeito da farinha (FCC) de cabeças de camarão (Penaeus spp.) sobre as variáveis produtivas, a qualidade física e avaliação sensorial do ovo fresco e armazenado, se utilizaram 120 galinhas Leghorn brancas de 42 semanas de idade, distribuídas em 5 tratamentos (0, 10, 15, 20 e 25% de FCC) com 4 repetições cada um. Aos 28 dias do ensaio se recolheram ovos de cada tratamento para avaliar a qualidade física aos 0, 15 e 30 dias de armazenamento a 4 e 20ºC, com um desenho fatorial de 5×3×2. Não houve diferenças estatísticas (P>0,05) nas variáveis produtivas. O peso médio do ovo foi maior (64,08g) com 15% de FCC, sem encontrar-se efeito pelo tempo de armazenamento. As Unidades Haugh (UH) dos ovos armazenados a 20ºC por 15 e 30 dias diminuíram, mas não a 4ºC. A cor da gema foi menor nos tratamentos com FCC em relação à testemunha e se viu afetado pelo tempo de armazenamento a 20ºC. O peso da carcaça não variou com as condições de armazenamento nem os tratamentos. Na espessura da carcaça e na avaliação sensorial (sabor e cor da gema), não houve diferenças (P>0,05). Conclui-se que as diferenças encontradas se deveram ao tempo e temperatura de armazenamento e não à inclusão de FCC nas rações para poedeiras.

The demand of feed for shrimp is growing worldwide. Therefore the search for new non-conventional ingredients, such as seaweeds is important for the elaboration of shrimp feed. Additionally, in view of the high concentration of cholesterol in shrimp, it was tested if the inclusion of the marine algae Sargassum can reduce the cholesterol content. The aim of this study was to evaluate the effect of a diet that contains Sargassum spp. on the productive parameters and the cholesterol concentration of brown shrimp (Farfantepenaeus californiensis). The trial was carried out during 45 days. Two diets were tested: one commercial diet (control treatment) and another with 4% dry weight of Sargassum meal. Four 60 L-tanks were used as replicas for each treatment. At the end of the bioassays, samples of shrimp muscle were taken, freeze-dried and total lipids, cholesterol content, triglycerides and proteins were determined. There were not significant differences in weight increments, size, survival rate and feed conversion between the two treatments. The cholesterol concentration in the shrimp fed with the diet that contained Sargassum was significantly (P<0,05) lower (77 mg/100 g) than in the shrimp fed with the control diet (110 mg/100 g). Our results show that is possible to include 4% of Sargassum meal in the diet for brown shrimp, without detrimental effects in their productive parameters and with a reduction of the cholesterol content.

La demanda de alimentos balanceados para camarón en cultivo tiene una tendencia creciente en el mundo, por lo que la búsqueda de nuevos ingredientes no convencionales como las algas marinas, para la elaboración de dichos alimentos cobra importancia, especialmente si éstos pueden reducir la concentración de colesterol en el camarón. El objetivo de este trabajo fue evaluar el efecto de una dieta que contiene 4% de harina de Sargassum spp. sobre los parámetros productivos y concentración de colesterol en el camarón café (Farfantepenaeus californiensis). Para ello se realizó un bioensayo con duración de 45 días, evaluando dos dietas: una comercial (tratamiento testigo) y otra que incluyó 4% de harina del alga Sargassum. Cuatro acuarios de 60 L fueron usados como réplicas para cada tratamiento. Al concluir el bioensayo se seleccionaron muestras de tejido muscular de camarones de los dos tratamientos, se liofilizaron y se les determinaron los lípidos totales, colesterol, triglicéridos y proteínas. No se encontraron diferencias significativas (P>0,05) en cuanto a ganancia de peso, talla, tasa de supervivencia y factor de conversión alimenticia entre los dos tratamientos. La concentración de colesterol en los camarones alimentados con la dieta que contenía Sargassum fue estadísticamente (P<0,05) menor (77 mg/100 g) que en los alimentados con la dieta testigo (110 mg/100 g). Los resultados obtenidos muestran que 4% de harina Sargassum puede ser incorporada a los alimentos balanceados para camarón café, sin causar efectos negativos en sus parámetros productivos y reduce la concentración de colesterol.

Abstract Copper (Cu) is used to promote growth in broilers. However, the optimum supplement level for improving productive performance is unknown. In the present study, an evaluation was made of the effect of eight levels (0, 50, 100, 150, 200, 250, 300, 350 mg kg−1) of Cu on the productive performance of sexed broilers, for the purpose of calculating the biological optimum level of Cu that maximizes weight gain (BOLWG), minimizes feed conversion (BOLFC), and the economic optimum level that maximizes profits (EOLMP). A completely randomized design was used with an 8×2 factorial arrangement. The means of the principal effects were compared with the Tukey test. Orthogonal contrasts were used to test linear, quadratic or cubic effects of the levels of Cu on productive performance. Econometric models were used to calculate the BOLWG, the BOLFC and the EOLMP. The levels of Cu did not affect the productive performance of the broilers of 1 to 21 d of age. The sex affected (p≤0.05) feed consumption, weight gain and live weight. In the stage of 22 to 42 d, differences (p≤0.05) were observed in feed consumption (CON), weight gain (WG), feed conversion (FC) and live weight (LW), due to the levels of Cu. The sex had no effect. Quadratic trends (p≤0.05) were detected for WG, FC and LW, and cubic (p≤0.05) for CONS and LW. The values for BOLWG, BOLFC and EOLMP were 122.99, 163.36 and 127.17 mg kg−1. The EOLMP was sensitive to the price changes of broilers.

Resumen El cobre (Cu) se utiliza como promotor de crecimiento en pollos de engorda, sin embargo se desconoce el nivel óptimo de suplemento para mejorar el comportamiento productivo. En este estudio se evaluó el efecto de ocho niveles (0, 50, 100, 150, 200, 250, 300, 350 mg kg−1) de Cu sobre el comportamiento productivo de pollos de engorda sexados, con el propósito de calcular el nivel óptimo biológico de Cu que maximice ganancia de peso (NOBGP), el que minimice conversión alimenticia (NOBCA) y el nivel óptimo económico que maximice utilidades (NOEMU). Se utilizó un diseño completamente al azar con arreglo factorial 8×2. Las medias de los efectos principales se compararon con la prueba de Tukey. Se probaron con contrastes ortogonales efectos lineales, cuadráticos o cúbicos de los niveles de Cu sobre el comportamiento productivo. Se utilizaron modelos econométricos para calcular el NOBGP, el NOBCA y el NOEMU. Los niveles de Cu no afectaron el comportamiento productivo de los pollos de 1 a 21 d de edad. El sexo afectó (p≤0.05) el consumo de alimento, la ganancia de peso y el peso vivo. En la fase de 22 a 42 d se observaron diferencias (p≤0.05) en consumo de alimento (CON), ganancia de peso (GP), conversión alimenticia (CA) y peso vivo (PV) debido a los niveles de Cu. El sexo no tuvo efecto. Se detectaron tendencias cuadráticas (p≤0.05) para GP, CA y PV, y cúbicas (p≤0.05) para CONS y PV. Los valores para NOBGP, NOBCA y NOEMU fueron 122.99, 163.36 y 127.17 mg kg−1. El NOEMU fue sensible a los cambios de precio del pollo de engorda.

La península de Baja California constituye una de las regiones más ricas en recursos algales de México. El objetivo de este trabajo fue conocer la composición química de algunas especies de algas marinas de Baja California Sur, consideradas económicamente potenciales por su distribución y abundancia y promover su empleo en la alimentación humana y animal. Las algas estudiadas fueron: Verdes (Ulva spp. , Enteromorpha intestinalis, Caulerpa sertularoides y Bryopsis hypnoides), Rojas (Laurencia johnstonii, Spyridia filamentosa e Hypnea valentiae) y Parda(Sargassum herporizum, S. sinicola, Padina durvillaei, Hydroclathrus clathrathus y Colpomenia sinuosa). Los ejemplares se secaron al sol y molieron en un molino de cuchillas. Los resultados mostraron en las algas, un contenido de proteína menor de 11%, excepto en L. Johnstonii con 18% y bajo aporte de energía. El contenido de extracto etéreo en general, fue menor al 1%. Las fracciones más abundantes resultaron ser los carbohidratos totales y la materia inorgánica, radicando en estos componentes químicos la principal riqueza de estos recursos.

Marine algae of Baja California Sur, México: nutrimental value. The Baja California Peninsula is one of the richest regions of seaweed resources in México. The objective of this study was to determine the chemical composition of some marine algae species of Baja California Sur, with an economical potential due to their abundance and distribution, and to promote their use as food for human consumption and animal feeding. The algae studied were Green (Ulva spp.,Enteromorpha intestinalis, Caulerpa sertularoides, Bryopsis hypnoides), Red (Laurencia johnstonii, Spyridia filamentosa, Hypnea valentiae) and Brown (Sargassum herporizum, S.sinicola, Padina durvillaei, Hydroclathrus clathrathus, Colpomenia sinuosa). The algae were dried and ground before analysis. In general, the results showed that algae had a protein level less than 11%, except L. johnstonii with 18% and low energy content. The ether extract content was lower than 1%. However, the algae were a good source of carbohydrates and inorganic matter.