azure service bus freaky contents

JAVA MESSAGE PRODUCER (using QPID libraries per Azure JMS tutorial):
 TextMessage message = sendSession.createTextMessage();
        message.setText("Test AMQP message from JMS");
        long randomMessageID = randomGenerator.nextLong() >>>1;
        message.setJMSMessageID("ID:" + randomMessageID);
        sender.send(message);
        System.out.println("Sent message with JMSMessageID = " + message.getJMSMessageID());

OUTPUT:
Sent message with JMSMessageID = ID:2414932965987073843

NODEJS MESSAGE CONSUMER:
serviceBus.receiveQueueMessage(queue, {timeoutIntervalInS: timeOut, isReceiveAndDelete: true}, function(err, message) {
if(message !==null)console.log(util.inspect(message, {showHidden: false, depth: null}));
});

OUTPUT:
{ body: '@\u0006string\b3http://schemas.microsoft.com/2003/10/Serialization/�\u001aTest AMQP message from JMS',
brokerProperties:
{ DeliveryCount: 1,
EnqueuedSequenceNumber: 5000004,
EnqueuedTimeUtc: 'Wed, 04 Nov 2015 21:28:21 GMT',
MessageId: '2414932965987073843',
PartitionKey: '89',
SequenceNumber: 59672695067659070,
State: 'Active',
TimeToLive: 1209600,
To: 'moequeue' },
contentType: 'application/xml; charset=utf-8' }


If I compare that to a message inserted into the queue via serviceBus.sendQueueMessage(), then the properties look like this:

{ body: 'test message',
brokerProperties:
{ DeliveryCount: 1,
EnqueuedSequenceNumber: 0,
EnqueuedTimeUtc: 'Wed, 04 Nov 2015 21:44:03 GMT',
MessageId: 'bc0a3d4f-15ba-434f-9fb0-1a3789885f8c',
PartitionKey: '734',
SequenceNumber: 37436171906517256,
State: 'Active',
TimeToLive: 1209600 },
contentType: 'text/plain',
customProperties:
{ message_number: 0,
sent_date: Wed Nov 04 2015 21:44:03 GMT+0000 (UTC) } }

So content type is different to start with - why? - and then where does the strange garbage in the body of the first message payload come from: @\u0006string\b3http://schemas.microsoft.com/2003/10/Serialization/�\u001a
Is that the result of serialization? How can this be mitigated?